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van der Horn HJ, Vakhtin AA, Julio K, Nitschke S, Shaff N, Dodd AB, Erhardt E, Phillips JP, Pirio Richardson S, Deligtisch A, Stewart M, Suarez Cedeno G, Meles SK, Mayer AR, Ryman SG. Parkinson's disease cerebrovascular reactivity pattern: A feasibility study. J Cereb Blood Flow Metab 2024:271678X241241895. [PMID: 38578669 DOI: 10.1177/0271678x241241895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 04/06/2024]
Abstract
A mounting body of research points to cerebrovascular dysfunction as a fundamental element in the pathophysiology of Parkinson's disease (PD). In the current feasibility study, blood-oxygen-level-dependent (BOLD) MRI was used to measure cerebrovascular reactivity (CVR) in response to hypercapnia in 26 PD patients and 16 healthy controls (HC), and aimed to find a multivariate pattern specific to PD. Whole-brain maps of CVR amplitude (i.e., magnitude of response to CO2) and latency (i.e., time to reach maximum amplitude) were computed, which were further analyzed using scaled sub-profile model principal component analysis (SSM-PCA) with leave-one-out cross-validation. A meaningful pattern based on CVR latency was identified, which was named the PD CVR pattern (PD-CVRP). This pattern was characterized by relatively increased latency in basal ganglia, sensorimotor cortex, supplementary motor area, thalamus and visual cortex, as well as decreased latency in the cerebral white matter, relative to HC. There were no significant associations with clinical measures, though sample size may have limited our ability to detect significant associations. In summary, the PD-CVRP highlights the importance of cerebrovascular dysfunction in PD, and may be a potential biomarker for future clinical research and practice.
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Affiliation(s)
- Harm Jan van der Horn
- Department of Translational Neuroscience, The Mind Research Network, Albuquerque, NM, USA
| | - Andrei A Vakhtin
- Department of Translational Neuroscience, The Mind Research Network, Albuquerque, NM, USA
| | - Kayla Julio
- Department of Translational Neuroscience, The Mind Research Network, Albuquerque, NM, USA
| | - Stephanie Nitschke
- Department of Translational Neuroscience, The Mind Research Network, Albuquerque, NM, USA
| | - Nicholas Shaff
- Department of Translational Neuroscience, The Mind Research Network, Albuquerque, NM, USA
| | - Andrew B Dodd
- Department of Translational Neuroscience, The Mind Research Network, Albuquerque, NM, USA
| | - Erik Erhardt
- Department of Mathematics and Statistics, University of New Mexico, Albuquerque, NM, USA
| | - John P Phillips
- Department of Translational Neuroscience, The Mind Research Network, Albuquerque, NM, USA
| | - Sarah Pirio Richardson
- Nene and Jamie Koch Comprehensive Movement Disorder Center, Department of Neurology, University of New Mexico, Albuquerque, NM, USA
- New Mexico VA Health Care System, Albuquerque, NM, USA
| | - Amanda Deligtisch
- Nene and Jamie Koch Comprehensive Movement Disorder Center, Department of Neurology, University of New Mexico, Albuquerque, NM, USA
| | - Melanie Stewart
- Nene and Jamie Koch Comprehensive Movement Disorder Center, Department of Neurology, University of New Mexico, Albuquerque, NM, USA
| | - Gerson Suarez Cedeno
- Nene and Jamie Koch Comprehensive Movement Disorder Center, Department of Neurology, University of New Mexico, Albuquerque, NM, USA
| | - Sanne K Meles
- Department of Neurology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Andrew R Mayer
- Department of Translational Neuroscience, The Mind Research Network, Albuquerque, NM, USA
| | - Sephira G Ryman
- Department of Translational Neuroscience, The Mind Research Network, Albuquerque, NM, USA
- Nene and Jamie Koch Comprehensive Movement Disorder Center, Department of Neurology, University of New Mexico, Albuquerque, NM, USA
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2
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Hou M, de Chastelaine M, Rugg MD. Age differences in the neural correlates of recollection: transient versus sustained fMRI effects. Neurobiol Aging 2023; 131:132-143. [PMID: 37633119 PMCID: PMC10528128 DOI: 10.1016/j.neurobiolaging.2023.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 06/28/2023] [Accepted: 07/02/2023] [Indexed: 08/28/2023]
Abstract
Prior functional magnetic resonance imaging findings in young adults indicate that recollection-sensitive neural regions dissociate according to the time courses of their respective recollection effects. Here, we examined whether such dissociations are also evident in older adults. Young and older participants encoded a series of word-image pairs, judging which of the denoted objects was the smaller. At the test, participants judged whether each of a series of test words was old or new. If a word was old, the requirement was to recall the associated image and maintain it over a variable delay period. Older adults demonstrated significantly lower associative memory performance than young adults. Transient recollection effects were identified in the left hippocampus, medial prefrontal cortex, and posterior cingulate, while sustained effects were widespread across left lateral cortex and were also evident in the bilateral striatum. Except for those in the left insula, all effects were age-invariant. These findings suggest that both transient and sustained recollection effects are largely stable across much of the healthy adult life span.
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Affiliation(s)
- Mingzhu Hou
- Center for Vital Longevity and School of Behavioral and Brain Sciences, The University of Texas at Dallas, Dallas, TX, USA.
| | - Marianne de Chastelaine
- Center for Vital Longevity and School of Behavioral and Brain Sciences, The University of Texas at Dallas, Dallas, TX, USA
| | - Michael D Rugg
- Center for Vital Longevity and School of Behavioral and Brain Sciences, The University of Texas at Dallas, Dallas, TX, USA
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de Chastelaine M, Horne ED, Hou M, Rugg MD. Relationships between age, fMRI correlates of familiarity and familiarity-based memory performance under single and dual task conditions. Neuropsychologia 2023; 189:108670. [PMID: 37633516 PMCID: PMC10591814 DOI: 10.1016/j.neuropsychologia.2023.108670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 08/22/2023] [Accepted: 08/23/2023] [Indexed: 08/28/2023]
Abstract
Using fMRI, we investigated the effects of age and divided attention on the neural correlates of familiarity and their relationship with memory performance. At study, word pairs were visually presented to young and older participants under the requirement to make a relational judgment on each pair. Participants were then scanned while undertaking an associative recognition test under single and dual (auditory tone detection) task conditions. The test items comprised studied, rearranged (words from different studied pairs) and new word pairs. fMRI familiarity effects were operationalized as greater activity elicited by studied pairs incorrectly identified as 'rearranged' than by correctly rejected new pairs. The reverse contrast was employed to identify 'novelty' effects. Behavioral familiarity estimates were equivalent across age groups and task conditions. Robust fMRI familiarity effects were identified in several regions, including medial and superior lateral parietal cortex, dorsal medial and left lateral prefrontal cortex, and bilateral caudate. fMRI novelty effects were identified in the anterior medial temporal lobe. Both familiarity and novelty effects were largely age-invariant and did not vary, or varied minimally, according to task condition. In addition, the familiarity effects correlated positively with a behavioral estimate of familiarity strength irrespective of age. These findings extend a previous report from our laboratory, and converge with prior behavioral reports, in demonstrating that the factors of age and divided attention have little impact on behavioral and neural estimates of familiarity.
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Affiliation(s)
- Marianne de Chastelaine
- Center for Vital Longevity and School of Behavioral and Brain Sciences, University of Texas, Dallas, TX, USA.
| | - Erin D Horne
- Center for Vital Longevity and School of Behavioral and Brain Sciences, University of Texas, Dallas, TX, USA
| | - Mingzhu Hou
- Center for Vital Longevity and School of Behavioral and Brain Sciences, University of Texas, Dallas, TX, USA
| | - Michael D Rugg
- Center for Vital Longevity and School of Behavioral and Brain Sciences, University of Texas, Dallas, TX, USA
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Ryman SG, Shaff N, Dodd A, Nitschke S, Wertz C, Julio K, Suarez Cedeno G, Deligtisch A, Erhardt E, Lin H, Vakhtin A, Poston KL, Tarawneh R, Pirio Richardson S, Mayer A. Reduced and Delayed Cerebrovascular Reactivity in Patients with Parkinson's Disease. Mov Disord 2023; 38:1262-1272. [PMID: 37157056 PMCID: PMC10524339 DOI: 10.1002/mds.29429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 04/17/2023] [Indexed: 05/10/2023] Open
Abstract
BACKGROUND Cerebrovascular dysfunction in Parkinson's disease (PD) is heterogeneous and may contribute to disease pathophysiology or progression. There is a need to understand the mechanisms by which cerebrovascular dysfunction is altered in participants with PD. OBJECTIVES The objective of this study is to test the hypothesis that participants with PD exhibit a significant reduction in the ability of the cerebral vessels to dilate in response to vasoactive challenges relative to healthy controls (HC). METHODS The current study uses a vasodilatory challenge while participants undergo functional magnetic resonance imaging to quantify the amplitude and delay of cerebrovascular reactivity in participants with PD relative to age and sex-matched HC. An analysis of covariance was used to evaluate differences in cerebrovascular reactivity amplitude and latency between PD participants and HC. RESULTS A significant main effect of group was observed for whole-brain cerebrovascular reactivity amplitude (F(1, 28) = 4.38, p = 0.046, Hedge's g = 0.73) and latency (F(1, 28) = 16.35, p < 0.001, Hedge's g = 1.42). Participants with PD exhibited reduced whole-brain amplitude and increased latencies in cerebrovascular reactivity relative to HC. The evaluation of regional effects indicates that the largest effects were observed in the cuneus, precuneus, and parietal regions. CONCLUSIONS PD participants exhibited reduced and delayed cerebrovascular reactivity. This dysfunction may play an important role in chronic hypoxia, neuroinflammation, and protein aggregation, mechanisms that could lead to disease progression. Cerebrovascular reactivity may serve as an important biomarker and target for future interventions. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Sephira G Ryman
- Department of Translational Neuroscience, The Mind Research Network, Albuquerque, New Mexico, USA
- Nene and Jamie Koch Comprehensive Movement Disorder Center, Department of Neurology, University of New Mexico, Albuquerque, New Mexico, USA
| | - Nicholas Shaff
- Department of Translational Neuroscience, The Mind Research Network, Albuquerque, New Mexico, USA
| | - Andrew Dodd
- Department of Translational Neuroscience, The Mind Research Network, Albuquerque, New Mexico, USA
| | - Stephanie Nitschke
- Department of Translational Neuroscience, The Mind Research Network, Albuquerque, New Mexico, USA
| | - Christopher Wertz
- Department of Translational Neuroscience, The Mind Research Network, Albuquerque, New Mexico, USA
| | - Kayla Julio
- Department of Translational Neuroscience, The Mind Research Network, Albuquerque, New Mexico, USA
| | - Gerson Suarez Cedeno
- Nene and Jamie Koch Comprehensive Movement Disorder Center, Department of Neurology, University of New Mexico, Albuquerque, New Mexico, USA
| | - Amanda Deligtisch
- Nene and Jamie Koch Comprehensive Movement Disorder Center, Department of Neurology, University of New Mexico, Albuquerque, New Mexico, USA
| | - Erik Erhardt
- Department of Mathematics and Statistics, University of New Mexico, Albuquerque, New Mexico, USA
| | - Henry Lin
- Department of Medicine, University of New Mexico, Albuquerque, New Mexico, USA
- Neurology|Medicine, New Mexico VA Health Care System, Albuquerque, New Mexico, USA
| | - Andrei Vakhtin
- Department of Translational Neuroscience, The Mind Research Network, Albuquerque, New Mexico, USA
| | - Kathleen L Poston
- Movement Disorders Division in the Department of Neurology and Neurological Sciences, Stanford University, Stanford, California, USA
| | - Rawan Tarawneh
- Memory and Aging Center, Department of Neurology, University of New Mexico, Albuquerque, New Mexico, USA
| | - Sarah Pirio Richardson
- Nene and Jamie Koch Comprehensive Movement Disorder Center, Department of Neurology, University of New Mexico, Albuquerque, New Mexico, USA
- Neurology|Medicine, New Mexico VA Health Care System, Albuquerque, New Mexico, USA
| | - Andrew Mayer
- Department of Translational Neuroscience, The Mind Research Network, Albuquerque, New Mexico, USA
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de Chastelaine M, Horne ED, Hou M, Rugg MD. Relationships between age, fMRI correlates of familiarity and familiarity-based memory performance under single and dual task conditions. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.26.542526. [PMID: 37398000 PMCID: PMC10312430 DOI: 10.1101/2023.05.26.542526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Using fMRI, we investigated the effects of age and divided attention on the neural correlates of familiarity and their relationship with memory performance. At study, word pairs were visually presented to young and older participants under the requirement to make a relational judgment on each pair. Participants were then scanned while undertaking an associative recognition test under single and dual (auditory tone detection) task conditions. The test items comprised studied, rearranged (words from different studied pairs) and new word pairs. fMRI familiarity effects were operationalized as greater activity elicited by studied pairs incorrectly identified as 'rearranged' than by correctly rejected new pairs. The reverse contrast was employed to identify 'novelty' effects. Behavioral familiarity estimates were equivalent across age groups and task conditions. Robust fMRI familiarity effects were identified in several regions, including medial and superior lateral parietal cortex, dorsal medial and left lateral prefrontal cortex, and bilateral caudate. fMRI novelty effects were identified in the anterior medial temporal lobe. Both familiarity and novelty effects were age-invariant and did not vary according to task condition. In addition, the familiarity effects correlated positively with a behavioral estimate of familiarity strength irrespective of age. These findings extend a previous report from our laboratory, and converge with prior behavioral reports, in demonstrating that the factors of age and divided attention have minimal impact on behavioral and neural estimates of familiarity.
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Williams RJ, Specht JL, Mazerolle EL, Lebel RM, MacDonald ME, Pike GB. Correspondence between BOLD fMRI task response and cerebrovascular reactivity across the cerebral cortex. Front Physiol 2023; 14:1167148. [PMID: 37228813 PMCID: PMC10203231 DOI: 10.3389/fphys.2023.1167148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 04/24/2023] [Indexed: 05/27/2023] Open
Abstract
BOLD sensitivity to baseline perfusion and blood volume is a well-acknowledged fMRI confound. Vascular correction techniques based on cerebrovascular reactivity (CVR) might reduce variance due to baseline cerebral blood volume, however this is predicated on an invariant linear relationship between CVR and BOLD signal magnitude. Cognitive paradigms have relatively low signal, high variance and involve spatially heterogenous cortical regions; it is therefore unclear whether the BOLD response magnitude to complex paradigms can be predicted by CVR. The feasibility of predicting BOLD signal magnitude from CVR was explored in the present work across two experiments using different CVR approaches. The first utilized a large database containing breath-hold BOLD responses and 3 different cognitive tasks. The second experiment, in an independent sample, calculated CVR using the delivery of a fixed concentration of carbon dioxide and a different cognitive task. An atlas-based regression approach was implemented for both experiments to evaluate the shared variance between task-invoked BOLD responses and CVR across the cerebral cortex. Both experiments found significant relationships between CVR and task-based BOLD magnitude, with activation in the right cuneus (R 2 = 0.64) and paracentral gyrus (R 2 = 0.71), and the left pars opercularis (R 2 = 0.67), superior frontal gyrus (R 2 = 0.62) and inferior parietal cortex (R 2 = 0.63) strongly predicted by CVR. The parietal regions bilaterally were highly consistent, with linear regressions significant in these regions for all four tasks. Group analyses showed that CVR correction increased BOLD sensitivity. Overall, this work suggests that BOLD signal response magnitudes to cognitive tasks are predicted by CVR across different regions of the cerebral cortex, providing support for the use of correction based on baseline vascular physiology.
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Affiliation(s)
- Rebecca J. Williams
- Faculty of Health, School of Human Services, Charles Darwin University, Darwin, NT, Australia
| | - Jacinta L. Specht
- Department of Clinical Neuroscience, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- Department of Radiology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Erin L. Mazerolle
- Departments of Psychology and Computer Science, St. Francis Xavier University, Antigonish, NS, Canada
| | - R. Marc Lebel
- Department of Radiology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- GE HealthCare, Calgary, AB, Canada
| | - M. Ethan MacDonald
- Department of Radiology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- Department of Biomedical Engineering, Schulich School of Engineering, University of Calgary, Calgary, AB, Canada
- Department of Electrical and Software Engineering, Schulich School of Engineering, University of Calgary, Calgary, AB, Canada
| | - G. Bruce Pike
- Department of Clinical Neuroscience, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- Department of Radiology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
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Hou M, de Chastelaine M, Rugg MD. The effects of age on neural correlates of recollection: transient versus sustained fMRI effects. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.12.536508. [PMID: 37090506 PMCID: PMC10120722 DOI: 10.1101/2023.04.12.536508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
Prior fMRI findings in young adults indicate that recollection-sensitive neural regions dissociate according to the time courses of their respective recollection effects. Here, we examined whether such dissociations are also evident in older adults. Young and older participants encoded a series of word-object image pairs, judging which of the denoted objects was the smaller. At test, participants first judged whether a test word was old or new. For items judged old, they were required to recall the associated image and hold it in mind across a variable delay period. A post-delay cue denoted which of three judgments should be made on the retrieved image. Older adults demonstrated significantly lower associative memory performance than young adults. Replicating prior findings, transient recollection effects were identified in the left hippocampus, medial prefrontal cortex and posterior cingulate, while sustained effects were widespread across left lateral cortex and were also evident in the bilateral striatum. With the exception of those in the left insula, all effects were age-invariant. These findings add to the evidence that recollection-related BOLD effects in different neural regions can be temporally dissociated. Additionally, the findings suggest that both transient and sustained recollection effects are largely stable across much of the healthy adult lifespan.
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López Pérez D, Bokde ALW, Kerskens CM. Complexity analysis of heartbeat-related signals in brain MRI time series as a potential biomarker for ageing and cognitive performance. THE EUROPEAN PHYSICAL JOURNAL. SPECIAL TOPICS 2022; 232:123-133. [PMID: 36910259 PMCID: PMC9988766 DOI: 10.1140/epjs/s11734-022-00696-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 09/27/2022] [Indexed: 06/18/2023]
Abstract
UNLABELLED Getting older affects both the structure of the brain and some cognitive capabilities. Until now, magnetic resonance imaging (MRI) approaches have been unable to give a coherent reflection of the cognitive declines. It shows the limitation of the contrast mechanisms used in most MRI investigations, which are indirect measures of brain activities depending on multiple physiological and cognitive variables. However, MRI signals may contain information of brain activity beyond these commonly used signals caused by the neurovascular response. Here, we apply a zero-spin echo (ZSE) weighted MRI sequence, which can detect heartbeat-evoked signals (HES). Remarkably, these MRI signals have properties only known from electrophysiology. We investigated the complexity of the HES arising from this sequence in two age groups; young (18-29 years) and old (over 65 years). While comparing young and old participants, we show that the complexity of the HES decreases with age, where the stability and chaoticity of these HES are particularly sensitive to age. However, we also found individual differences which were independent of age. Complexity measures were related to scores from different cognitive batteries and showed that higher complexity may be related to better cognitive performance. These findings underpin the affinity of the HES to electrophysiological signals. The profound sensitivity of these changes in complexity shows the potential of HES for understanding brain dynamics that need to be tested in more extensive and diverse populations with clinical relevance for all neurovascular diseases. SUPPLEMENTARY INFORMATION The online version contains supplementary material available at 10.1140/epjs/s11734-022-00696-2.
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Affiliation(s)
- David López Pérez
- Institute of Psychology, Polish Academy of Sciences, Warsaw, Poland
- Institute of Neuroscience, Trinity College, Dublin, Ireland
| | - Arun L. W. Bokde
- Trinity College Institute of Neuroscience and Cognitive Systems Group, Discipline of Psychiatry, School of Medicine, Trinity College Dublin, Dublin, Ireland
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Wu S, Tyler LK, Henson RN, Rowe JB, Cam-CAN, Tsvetanov KA. Cerebral blood flow predicts multiple demand network activity and fluid intelligence across the adult lifespan. Neurobiol Aging 2022; 121:1-14. [PMID: 36306687 PMCID: PMC7613814 DOI: 10.1016/j.neurobiolaging.2022.09.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 09/13/2022] [Accepted: 09/14/2022] [Indexed: 10/14/2022]
Abstract
The preservation of cognitive function in old age is a public health priority. Cerebral hypoperfusion is a hallmark of dementia but its impact on maintaining cognitive ability across the lifespan is less clear. We investigated the relationship between baseline cerebral blood flow (CBF) and blood oxygenation level-dependent (BOLD) response during a fluid reasoning task in a population-based adult lifespan cohort. As age differences in CBF could lead to non-neuronal contributions to the BOLD signal, we introduced commonality analysis to neuroimaging to dissociate performance-related CBF effects from the physiological confounding effects of CBF on the BOLD response. Accounting for CBF, we confirmed that performance- and age-related differences in BOLD responses in the multiple-demand network were implicated in fluid reasoning. Age differences in CBF explained not only performance-related BOLD responses but also performance-independent BOLD responses. Our results suggest that CBF is important for maintaining cognitive function, while its non-neuronal contributions to BOLD signals reflect an age-related confound. Maintaining perfusion into old age may serve to support brain function and preserve cognitive performance.
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Affiliation(s)
- Shuyi Wu
- Centre for Speech, Language and the Brain, Department of Psychology, University of Cambridge, Cambridge, UK,Department of Management, School of Business, Hong Kong Baptist University, Hong Kong, China
| | - Lorraine K. Tyler
- Centre for Speech, Language and the Brain, Department of Psychology, University of Cambridge, Cambridge, UK
| | - Richard N.A. Henson
- Medical Research Council Cognition and Brain Sciences Unit, Department of Psychiatry, Cambridge, UK
| | - James B. Rowe
- Medical Research Council Cognition and Brain Sciences Unit, Department of Psychiatry, Cambridge, UK,Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Cam-CAN
- Centre for Speech, Language and the Brain, Department of Psychology, University of Cambridge, Cambridge, UK,Medical Research Council Cognition and Brain Sciences Unit, Department of Psychiatry, Cambridge, UK
| | - Kamen A. Tsvetanov
- Centre for Speech, Language and the Brain, Department of Psychology, University of Cambridge, Cambridge, UK,Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK,Corresponding author (, +44 1223 766 556)
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10
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Peng SL, Chu LWL, Su FY. Cerebral hemodynamic response to caffeine: effect of dietary caffeine consumption. NMR IN BIOMEDICINE 2022; 35:e4727. [PMID: 35285102 DOI: 10.1002/nbm.4727] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 02/14/2022] [Accepted: 03/06/2022] [Indexed: 06/14/2023]
Abstract
Caffeine has a significant effect on cerebrovascular systems, and the dual action of caffeine on both neural and vascular responses leads to concerns for the interpretation of blood oxygenation level-dependent (BOLD) functional MRI. However, potential differences in the brain response to caffeine with regard to consumption habits have not been fully elucidated, as BOLD responses may vary with the dietary caffeine consumption history. The main aim of this study was to characterize the acute effect of caffeine on cerebral hemodynamic responses in participants with different patterns of caffeine consumption habits. Fifteen non-habitual and 11 habitual volunteers were included in this study. The cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) to the breath-hold challenge were measured before and after 200 mg caffeine administration. The non-habitual individuals exhibited a pattern of progressive reduction in CBF with time. The CVR was diminished in the caffeinated condition (P < 0.05). In the habitual group, the pattern of CBF decrease was smaller and homogeneous across the brain, and reached steady state rapidly. The CVR was not affected in the presence of caffeine (P > 0.05). Our results demonstrated that the cerebral hemodynamic response to caffeine was subject to the habitual consumption patterns of the participants. The compromised CVR following caffeine administration in the non-habitual group may partially explain the suppressed BOLD response to a visual stimulation in low-caffeine-level users.
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Affiliation(s)
- Shin-Lei Peng
- Department of Biomedical Imaging and Radiological Science, China Medical University, Taichung, Taiwan
| | - Lok Wang Lauren Chu
- Department of Biomedical Imaging and Radiological Science, China Medical University, Taichung, Taiwan
| | - Feng-Yi Su
- Department of Medical Imaging, China Medical University Hospital, Taichung, Taiwan
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11
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Stickland RC, Zvolanek KM, Moia S, Caballero-Gaudes C, Bright MG. Lag-Optimized Blood Oxygenation Level Dependent Cerebrovascular Reactivity Estimates Derived From Breathing Task Data Have a Stronger Relationship With Baseline Cerebral Blood Flow. Front Neurosci 2022; 16:910025. [PMID: 35801183 PMCID: PMC9254683 DOI: 10.3389/fnins.2022.910025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 05/11/2022] [Indexed: 11/13/2022] Open
Abstract
Cerebrovascular reactivity (CVR), an important indicator of cerebrovascular health, is commonly studied with the Blood Oxygenation Level Dependent functional MRI (BOLD-fMRI) response to a vasoactive stimulus. Theoretical and empirical evidence suggests that baseline cerebral blood flow (CBF) modulates BOLD signal amplitude and may influence BOLD-CVR estimates. We address how acquisition and modeling choices affect the relationship between baseline cerebral blood flow (bCBF) and BOLD-CVR: whether BOLD-CVR is modeled with the inclusion of a breathing task, and whether BOLD-CVR amplitudes are optimized for hemodynamic lag effects. We assessed between-subject correlations of average GM values and within-subject spatial correlations across cortical regions. Our results suggest that a breathing task addition to a resting-state acquisition, alongside lag-optimization within BOLD-CVR modeling, can improve BOLD-CVR correlations with bCBF, both between- and within-subjects, likely because these CVR estimates are more physiologically accurate. We report positive correlations between bCBF and BOLD-CVR, both between- and within-subjects. The physiological explanation of this positive correlation is unclear; research with larger samples and tightly controlled vasoactive stimuli is needed. Insights into what drives variability in BOLD-CVR measurements and related measurements of cerebrovascular function are particularly relevant when interpreting results in populations with altered vascular and/or metabolic baselines or impaired cerebrovascular reserve.
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Affiliation(s)
- Rachael C. Stickland
- Department of Physical Therapy and Human Movement Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Kristina M. Zvolanek
- Department of Physical Therapy and Human Movement Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
- Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Evanston, IL, United States
| | - Stefano Moia
- Basque Center on Cognition, Brain and Language, Donostia, Spain
- University of the Basque Country EHU/UPV, Donostia, Spain
| | | | - Molly G. Bright
- Department of Physical Therapy and Human Movement Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
- Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Evanston, IL, United States
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12
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Chen X, Rundle MM, Kennedy KM, Moore W, Park DC. Functional activation features of memory in successful agers across the adult lifespan. Neuroimage 2022; 257:119276. [PMID: 35523368 PMCID: PMC9364925 DOI: 10.1016/j.neuroimage.2022.119276] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 04/23/2022] [Accepted: 05/01/2022] [Indexed: 11/01/2022] Open
Abstract
Much neuroimaging research has explored the neural mechanisms underlying successful cognitive aging. Two different patterns of functional activation, maintenance of youth-like activity and compensatory novel recruitment, have been proposed to represent different brain functional features underlying individual differences in cognitive aging. In this study, we investigated the functional features in individuals across the adult lifespan who appeared to resist age-related cognitive decline, in comparison to those with typical age-related declines, over the course of four years. We first implemented latent mixture modeling, a data-driven approach, to classify participants as successful and average agers in middle-aged, young-old, and very old groups, based on their baseline and longitudinal cognitive performance. Then, using fMRI with a subsequent memory paradigm at the follow-up visit, brain activation specifically related to successful encoding (i.e., subsequent memory effect: subsequently remembered with high confidence > subsequently forgotten) was compared between people who established successful cognitive aging versus average aging in the three age groups. Several differences in the subsequent memory effect were revealed. First, across core task-related regions commonly used during successful encoding, successful agers exhibited high subsequent memory effect, at a level comparable to the young control group, until very old age; in contrast, average agers showed reduced subsequent memory effect, compared to successful agers, beginning in young-old age when memory performance also reduced in average agers, compared to successful agers. Second, additional recruitment in prefrontal clusters, distant from the core task-related regions, were identified in the left superior frontal and right orbitofrontal cortices in successful agers of young-old age, possibly reflecting functional compensation in successful aging. In summary, successful agers demonstrate a pattern of youth-like activation spanning from middle age to young-old age, as well as novel frontal recruitment in young-old age. Overall, our study demonstrated evidence of two neural patterns related to successful cognitive aging, offering an integrated view of functional features underlying successful aging, and suggests the importance of studying individuals across the lifespan to understand brain changes occurring in mid and early-late life.
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Affiliation(s)
- Xi Chen
- Center for Vital Longevity, School of Behavioral and Brain Sciences, The University of Texas at Dallas, 1600 Viceroy Dr., Unit 800, Dallas, TX, 75235, USA.
| | - Melissa M Rundle
- Center for Vital Longevity, School of Behavioral and Brain Sciences, The University of Texas at Dallas, 1600 Viceroy Dr., Unit 800, Dallas, TX, 75235, USA
| | - Kristen M Kennedy
- Center for Vital Longevity, School of Behavioral and Brain Sciences, The University of Texas at Dallas, 1600 Viceroy Dr., Unit 800, Dallas, TX, 75235, USA
| | - William Moore
- Department of Radiology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX, USA
| | - Denise C Park
- Center for Vital Longevity, School of Behavioral and Brain Sciences, The University of Texas at Dallas, 1600 Viceroy Dr., Unit 800, Dallas, TX, 75235, USA
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13
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Mayhew SD, Coleman SC, Mullinger KJ, Can C. Across the adult lifespan the ipsilateral sensorimotor cortex negative BOLD response exhibits decreases in magnitude and spatial extent suggesting declining inhibitory control. Neuroimage 2022; 253:119081. [PMID: 35278710 PMCID: PMC9130740 DOI: 10.1016/j.neuroimage.2022.119081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 03/07/2022] [Accepted: 03/07/2022] [Indexed: 11/27/2022] Open
Abstract
Ipsilateral sensorimotor (iSM1) cortex negative BOLD responses (NBR) are observed to unilateral tasks and are thought to reflect a functionally relevant component of sensorimotor inhibition. Evidence suggests that sensorimotor inhibitory mechanisms degrade with age, along with aspects of motor ability and dexterity. However, understanding of age-related changes to NBR is restricted by limited comparisons between young vs old adults groups with relatively small samples sizes. Here we analysed a BOLD fMRI dataset (obtained from the CamCAN repository) of 581 healthy subjects, gender-balanced, sampled from the whole adult lifespan performing a motor response task to an audio-visual stimulus. We aimed to investigate how sensorimotor and default-mode NBR characteristics of magnitude, spatial extent and response shape alter at every decade of the aging process. A linear decrease in iSM1 NBR magnitude was observed across the whole lifespan whereas the contralateral sensorimotor (cSM1) PBR magnitude was unchanged. An age-related decrease in the spatial extent of NBR and an increase in the ipsilateral positive BOLD response (PBR) was observed. This occurred alongside an increasing negative correlation between subject's iSM1 NBR and cSM1 PBR magnitude, reflecting a change in the balance between cortical excitation and inhibition. Conventional GLM analysis, using a canonical haemodynamic response (HR) function, showed disappearance of iSM1 NBR in subjects over 50 years of age. However, a deconvolution analysis showed that the shape of the iSM1 HR altered throughout the lifespan, with delayed time-to-peak and decreased magnitude. The most significant decreases in iSM1 HR magnitude occurred in older age (>60 years) but the first changes in shape and timing occurred as early as 30 years, suggesting possibility of separate mechanisms underlying these alterations. Reanalysis using data-driven HRs for each decade detected significant sensorimotor NBR into late older age, showing the importance of taking changes in HR morphology into account in fMRI aging studies. These results may reflect fMRI measures of the age-related decreases in transcollosal inhibition exerted upon ipsilateral sensorimotor cortex and alterations to the excitatory-inhibitory balance in the sensorimotor network.
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Affiliation(s)
- Stephen D Mayhew
- Centre for Human Brain Health (CHBH), School of Psychology, University of Birmingham, Birmingham, UK.
| | - Sebastian C Coleman
- Sir Peter Mansfield Imaging Centre (SPMIC), School of Physics and Astronomy, University of Nottingham, Nottingham, UK
| | - Karen J Mullinger
- Centre for Human Brain Health (CHBH), School of Psychology, University of Birmingham, Birmingham, UK; Sir Peter Mansfield Imaging Centre (SPMIC), School of Physics and Astronomy, University of Nottingham, Nottingham, UK
| | - Cam Can
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
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14
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Hou M, Horne ED, de Chastelaine M, Rugg MD. Divided attention at retrieval does not influence neural correlates of recollection in young or older adults. Neuroimage 2022; 250:118918. [PMID: 35051582 PMCID: PMC8885896 DOI: 10.1016/j.neuroimage.2022.118918] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 01/12/2022] [Accepted: 01/15/2022] [Indexed: 01/23/2023] Open
Abstract
Age-related decline in episodic memory has been partially attributed to older adults' reduced domain general processing resources. In the present study, we examined the effects of divided attention (DA) - a manipulation assumed to further deplete the already limited processing resources of older adults - on the neural correlates of recollection in young and older adults. Participants underwent fMRI scanning while they performed an associative recognition test in single and dual (tone detection) task conditions. Recollection effects were operationalized as greater BOLD activity elicited by test pairs correctly endorsed as 'intact' than pairs correctly or incorrectly endorsed as 'rearranged'. Detrimental effects of DA on associative recognition performance were identified in older but not young adults. The magnitudes of recollection effects did not differ between the single and dual (tone detection) tasks in either age group. Across the task conditions, age-invariant recollection effects were evident in most members of the core recollection network. However, while young adults demonstrated robust recollection effects in left angular gyrus, angular gyrus effects were undetectable in the older adults in either task condition. With the possible exception of this result, the findings suggest that DA did not influence processes supporting the retrieval and representation of associative information in either young or older adults, and converge with prior behavioral findings to suggest that episodic retrieval operations are little affected by DA.
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Affiliation(s)
- Mingzhu Hou
- Center for Vital Longevity and School of Behavioral and Brain Sciences, The University of Texas at Dallas, Dallas, TX 75235, USA.
| | - Erin D Horne
- Center for Vital Longevity and School of Behavioral and Brain Sciences, The University of Texas at Dallas, Dallas, TX 75235, USA; Center for BrainHealth and School of Behavioral and Brain Sciences, The University of Texas at Dallas, Dallas, TX 75235, USA
| | - Marianne de Chastelaine
- Center for Vital Longevity and School of Behavioral and Brain Sciences, The University of Texas at Dallas, Dallas, TX 75235, USA
| | - Michael D Rugg
- Center for Vital Longevity and School of Behavioral and Brain Sciences, The University of Texas at Dallas, Dallas, TX 75235, USA; School of Psychology, University of East Anglia, Norwich NR4 7TJ, UK
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15
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Liu P, Jiang D, Albert M, Bauer CE, Caprihan A, Gold BT, Greenberg SM, Helmer KG, Jann K, Jicha G, Rodriguez P, Satizabal CL, Seshadri S, Singh H, Thompson JF, Wang DJJ, Lu H. Multi-vendor and multisite evaluation of cerebrovascular reactivity mapping using hypercapnia challenge. Neuroimage 2021; 245:118754. [PMID: 34826595 PMCID: PMC8783393 DOI: 10.1016/j.neuroimage.2021.118754] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 11/05/2021] [Accepted: 11/22/2021] [Indexed: 01/22/2023] Open
Abstract
Cerebrovascular reactivity (CVR), which measures the ability of cerebral blood vessels to dilate or constrict in response to vasoactive stimuli such as CO2 inhalation, is an important index of the brain's vascular health. Quantification of CVR using BOLD MRI with hypercapnia challenge has shown great promises in research and clinical studies. However, in order for it to be used as a potential imaging biomarker in large-scale and multi-site studies, the reliability of CO2-CVR quantification across different MRI acquisition platforms and researchers/raters must be examined. The goal of this report from the MarkVCID small vessel disease biomarkers consortium is to evaluate the reliability of CO2-CVR quantification in three studies. First, the inter-rater reliability of CO2-CVR data processing was evaluated by having raters from 5 MarkVCID sites process the same 30 CVR datasets using a cloud-based CVR data processing pipeline. Second, the inter-scanner reproducibility of CO2-CVR quantification was assessed in 10 young subjects across two scanners of different vendors. Third, test-retest repeatability was evaluated in 20 elderly subjects from 4 sites with a scan interval of less than 2 weeks. In all studies, the CO2 CVR measurements were performed using the fixed inspiration method, where the subjects wore a nose clip and a mouthpiece and breathed room air and 5% CO2 air contained in a Douglas bag alternatively through their mouth. The results showed that the inter-rater CoV of CVR processing was 0.08 ± 0.08% for whole-brain CVR values and ranged from 0.16% to 0.88% in major brain regions, with ICC of absolute agreement above 0.9959 for all brain regions. Inter-scanner CoV was found to be 6.90 ± 5.08% for whole-brain CVR values, and ranged from 4.69% to 12.71% in major brain regions, which are comparable to intra-session CoVs obtained from the same scanners on the same day. ICC of consistency between the two scanners was 0.8498 for whole-brain CVR and ranged from 0.8052 to 0.9185 across major brain regions. In the test-retest evaluation, test-retest CoV across different days was found to be 18.29 ± 17.12% for whole-brain CVR values, and ranged from 16.58% to 19.52% in major brain regions, with ICC of absolute agreement ranged from 0.6480 to 0.7785. These results demonstrated good inter-rater, inter-scanner, and test-retest reliability in healthy volunteers, and suggested that CO2-CVR has suitable instrumental properties for use as an imaging biomarker of cerebrovascular function in multi-site and longitudinal observational studies and clinical trials.
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Affiliation(s)
- Peiying Liu
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Dengrong Jiang
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Marilyn Albert
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | | | | | - Brian T Gold
- Department of Neuroscience, University of Kentucky, Lexington, KY, USA
| | - Steven M Greenberg
- Department of Neurology, Massachusetts General Hospital Stroke Research Center, Harvard Medical School, Boston, MA, USA
| | - Karl G Helmer
- Department of Radiology, Massachusetts General Hospital, Boston, MA, USA
| | - Kay Jann
- Laboratory of Functional MRI Technology, Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Gregory Jicha
- Department of Neurology, University of Kentucky, Lexington, KY, USA
| | - Pavel Rodriguez
- Department of Radiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA; Glenn Biggs Institute for Alzheimer's and Neurodegenerative Diseases, UT Health San Antonio, San Antonio, TX, USA
| | - Claudia L Satizabal
- Glenn Biggs Institute for Alzheimer's and Neurodegenerative Diseases, UT Health San Antonio, San Antonio, TX, USA
| | - Sudha Seshadri
- Glenn Biggs Institute for Alzheimer's and Neurodegenerative Diseases, UT Health San Antonio, San Antonio, TX, USA
| | - Herpreet Singh
- Department of Radiology, Massachusetts General Hospital, Boston, MA, USA
| | - Jeffrey F Thompson
- Department of Neurology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, USA
| | - Danny J J Wang
- Laboratory of Functional MRI Technology, Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Hanzhang Lu
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore 21287, USA; F.M. Kirby Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, 21205, USA.
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16
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Hou M, Wang TH, Rugg MD. The effects of age on neural correlates of recognition memory: An fMRI study. Brain Cogn 2021; 153:105785. [PMID: 34419811 PMCID: PMC8429125 DOI: 10.1016/j.bandc.2021.105785] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Revised: 07/23/2021] [Accepted: 07/29/2021] [Indexed: 11/19/2022]
Abstract
Studies examining the effects of age on the neural correlates of recognition memory have yielded mixed results. In the present study, we employed a modified remember-know paradigm to compare the fMRI correlates of recollection and familiarity in samples of healthy young and older adults. After studying a series of words, participants underwent fMRI scanning during a test phase in which they responded "remember" to a test word if any qualitative information could be recollected about the study event. When recollection failed, participants signaled how confident they were that the test item had been studied. Young and older adults demonstrated statistically equivalent estimates of recollection and familiarity strength, while recognition memory accuracy was significantly lower in the older adults. Robust, age-invariant fMRI effects were evident in two sets of a priori defined brain regions consistently reported in prior studies to be sensitive to recollection and familiarity respectively. In addition, the magnitudes of 'familiarity-attenuation effects' in perirhinal cortex demonstrated age-invariant correlations with estimates of familiarity strength and memory accuracy, replicating prior findings. Together, the present findings add to the evidence that the neural correlates of recognition memory are largely stable across much of the healthy human adult lifespan.
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Affiliation(s)
- Mingzhu Hou
- Center for Vital Longevity and School of Behavioral and Brain Sciences, The University of Texas at Dallas, Dallas, TX 75235, USA.
| | - Tracy H Wang
- Center for Vital Longevity and School of Behavioral and Brain Sciences, The University of Texas at Dallas, Dallas, TX 75235, USA
| | - Michael D Rugg
- Center for Vital Longevity and School of Behavioral and Brain Sciences, The University of Texas at Dallas, Dallas, TX 75235, USA; School of Psychology, University of East Anglia, Norwich NR4 7TJ, UK
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17
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Tsvetanov KA, Henson RNA, Jones PS, Mutsaerts H, Fuhrmann D, Tyler LK, Rowe JB. The effects of age on resting-state BOLD signal variability is explained by cardiovascular and cerebrovascular factors. Psychophysiology 2021; 58:e13714. [PMID: 33210312 PMCID: PMC8244027 DOI: 10.1111/psyp.13714] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 07/27/2020] [Accepted: 09/28/2020] [Indexed: 12/18/2022]
Abstract
Accurate identification of brain function is necessary to understand neurocognitive aging, and thereby promote health and well-being. Many studies of neurocognitive aging have investigated brain function with the blood-oxygen level-dependent (BOLD) signal measured by functional magnetic resonance imaging. However, the BOLD signal is a composite of neural and vascular signals, which are differentially affected by aging. It is, therefore, essential to distinguish the age effects on vascular versus neural function. The BOLD signal variability at rest (known as resting state fluctuation amplitude, RSFA), is a safe, scalable, and robust means to calibrate vascular responsivity, as an alternative to breath-holding and hypercapnia. However, the use of RSFA for normalization of BOLD imaging assumes that age differences in RSFA reflecting only vascular factors, rather than age-related differences in neural function (activity) or neuronal loss (atrophy). Previous studies indicate that two vascular factors, cardiovascular health (CVH) and cerebrovascular function, are insufficient when used alone to fully explain age-related differences in RSFA. It remains possible that their joint consideration is required to fully capture age differences in RSFA. We tested the hypothesis that RSFA no longer varies with age after adjusting for a combination of cardiovascular and cerebrovascular measures. We also tested the hypothesis that RSFA variation with age is not associated with atrophy. We used data from the population-based, lifespan Cam-CAN cohort. After controlling for cardiovascular and cerebrovascular estimates alone, the residual variance in RSFA across individuals was significantly associated with age. However, when controlling for both cardiovascular and cerebrovascular estimates, the variance in RSFA was no longer associated with age. Grey matter volumes did not explain age differences in RSFA, after controlling for CVH. The results were consistent between voxel-level analysis and independent component analysis. Our findings indicate that cardiovascular and cerebrovascular signals are together sufficient predictors of age differences in RSFA. We suggest that RSFA can be used to separate vascular from neuronal factors, to characterize neurocognitive aging. We discuss the implications and make recommendations for the use of RSFA in the research of aging.
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Affiliation(s)
- Kamen A. Tsvetanov
- Department of Clinical NeurosciencesUniversity of CambridgeCambridgeUK
- Department of PsychologyCentre for Speech, Language and the BrainUniversity of CambridgeCambridgeUK
| | - Richard N. A. Henson
- Medical Research Council Cognition and Brain Sciences UnitCambridgeUK
- Department of PsychiatryUniversity of CambridgeCambridgeUK
| | - P. Simon Jones
- Department of PsychologyCentre for Speech, Language and the BrainUniversity of CambridgeCambridgeUK
| | - Henk Mutsaerts
- Department of Radiology and Nuclear MedicineAmsterdam University Medical CenterAmsterdamthe Netherlands
| | - Delia Fuhrmann
- Medical Research Council Cognition and Brain Sciences UnitCambridgeUK
| | - Lorraine K. Tyler
- Department of PsychologyCentre for Speech, Language and the BrainUniversity of CambridgeCambridgeUK
| | - Cam‐CAN
- Department of Clinical NeurosciencesUniversity of CambridgeCambridgeUK
- Department of PsychologyCentre for Speech, Language and the BrainUniversity of CambridgeCambridgeUK
| | - James B. Rowe
- Department of Clinical NeurosciencesUniversity of CambridgeCambridgeUK
- Medical Research Council Cognition and Brain Sciences UnitCambridgeUK
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18
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Zhao Y, Liu P, Turner MP, Abdelkarim D, Lu H, Rypma B. The neural-vascular basis of age-related processing speed decline. Psychophysiology 2021; 58:e13845. [PMID: 34115388 DOI: 10.1111/psyp.13845] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 04/14/2021] [Accepted: 04/19/2021] [Indexed: 12/12/2022]
Abstract
Most studies examining neurocognitive aging are based on the blood-oxygen level-dependent signal obtained during functional magnetic resonance imaging (fMRI). The physiological basis of this signal is neural-vascular coupling, the process by which neurons signal cerebrovasculature to dilate in response to an increase in active neural metabolism due to stimulation. These fMRI studies of aging rely on the hemodynamic equivalence assumption that this process is not disrupted by physiologic deterioration associated with aging. Studies of neural-vascular coupling challenge this assumption and show that neural-vascular coupling is closely related to cognition. In this review, we put forward a theory of processing speed decline in aging and how it is related to age-related neural-vascular coupling changes based on the results of studies elucidating the relationships between cognition, cerebrovascular dynamics, and aging.
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Affiliation(s)
- Yuguang Zhao
- School of Behavioral and Brain Sciences, Center for Brain Health, University of Texas at Dallas, Richardson, TX, USA
| | - Peiying Liu
- School of Medicine, Department of Radiology, Johns Hopkins University, Baltimore, MD, USA
| | - Monroe P Turner
- School of Behavioral and Brain Sciences, Center for Brain Health, University of Texas at Dallas, Richardson, TX, USA
| | - Dema Abdelkarim
- School of Behavioral and Brain Sciences, Center for Brain Health, University of Texas at Dallas, Richardson, TX, USA
| | - Hanzhang Lu
- School of Medicine, Department of Radiology, Johns Hopkins University, Baltimore, MD, USA
| | - Bart Rypma
- School of Behavioral and Brain Sciences, Center for Brain Health, University of Texas at Dallas, Richardson, TX, USA
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19
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Chen JJ, Gauthier CJ. The Role of Cerebrovascular-Reactivity Mapping in Functional MRI: Calibrated fMRI and Resting-State fMRI. Front Physiol 2021; 12:657362. [PMID: 33841190 PMCID: PMC8027080 DOI: 10.3389/fphys.2021.657362] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 03/02/2021] [Indexed: 12/14/2022] Open
Abstract
Task and resting-state functional MRI (fMRI) is primarily based on the same blood-oxygenation level-dependent (BOLD) phenomenon that MRI-based cerebrovascular reactivity (CVR) mapping has most commonly relied upon. This technique is finding an ever-increasing role in neuroscience and clinical research as well as treatment planning. The estimation of CVR has unique applications in and associations with fMRI. In particular, CVR estimation is part of a family of techniques called calibrated BOLD fMRI, the purpose of which is to allow the mapping of cerebral oxidative metabolism (CMRO2) using a combination of BOLD and cerebral-blood flow (CBF) measurements. Moreover, CVR has recently been shown to be a major source of vascular bias in computing resting-state functional connectivity, in much the same way that it is used to neutralize the vascular contribution in calibrated fMRI. Furthermore, due to the obvious challenges in estimating CVR using gas challenges, a rapidly growing field of study is the estimation of CVR without any form of challenge, including the use of resting-state fMRI for that purpose. This review addresses all of these aspects in which CVR interacts with fMRI and the role of CVR in calibrated fMRI, provides an overview of the physiological biases and assumptions underlying hypercapnia-based CVR and calibrated fMRI, and provides a view into the future of non-invasive CVR measurement.
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Affiliation(s)
- J Jean Chen
- Baycrest Centre for Geriatric Care, Rotman Research Institute, Toronto, ON, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - Claudine J Gauthier
- Department of Physics, Concordia University, Montreal, QC, Canada.,Montreal Heart Institute, Montreal, QC, Canada
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20
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Krishnamurthy V, Sprick JD, Krishnamurthy LC, Barter JD, Turabi A, Hajjar IM, Nocera JR. The Utility of Cerebrovascular Reactivity MRI in Brain Rehabilitation: A Mechanistic Perspective. Front Physiol 2021; 12:642850. [PMID: 33815146 PMCID: PMC8009989 DOI: 10.3389/fphys.2021.642850] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 02/22/2021] [Indexed: 01/06/2023] Open
Abstract
Cerebrovascular control and its integration with other physiological systems play a key role in the effective maintenance of homeostasis in brain functioning. Maintenance, restoration, and promotion of such a balance are one of the paramount goals of brain rehabilitation and intervention programs. Cerebrovascular reactivity (CVR), an index of cerebrovascular reserve, plays an important role in chemo-regulation of cerebral blood flow. Improved vascular reactivity and cerebral blood flow are important factors in brain rehabilitation to facilitate desired cognitive and functional outcomes. It is widely accepted that CVR is impaired in aging, hypertension, and cerebrovascular diseases and possibly in neurodegenerative syndromes. However, a multitude of physiological factors influence CVR, and thus a comprehensive understanding of underlying mechanisms are needed. We are currently underinformed on which rehabilitation method will improve CVR, and how this information can inform on a patient's prognosis and diagnosis. Implementation of targeted rehabilitation regimes would be the first step to elucidate whether such regimes can modulate CVR and in the process may assist in improving our understanding for the underlying vascular pathophysiology. As such, the high spatial resolution along with whole brain coverage offered by MRI has opened the door to exciting recent developments in CVR MRI. Yet, several challenges currently preclude its potential as an effective diagnostic and prognostic tool in treatment planning and guidance. Understanding these knowledge gaps will ultimately facilitate a deeper understanding for cerebrovascular physiology and its role in brain function and rehabilitation. Based on the lessons learned from our group's past and ongoing neurorehabilitation studies, we present a systematic review of physiological mechanisms that lead to impaired CVR in aging and disease, and how CVR imaging and its further development in the context of brain rehabilitation can add value to the clinical settings.
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Affiliation(s)
- Venkatagiri Krishnamurthy
- Center for Visual and Neurocognitive Rehabilitation, Atlanta VAMC, Decatur, GA, United States
- Division of Geriatrics and Gerontology, Department of Medicine, Emory University, Atlanta, GA, United States
- Department of Neurology, Emory University, Atlanta, GA, United States
| | - Justin D. Sprick
- Division of Renal Medicine, Department of Medicine, Emory University, Atlanta, GA, United States
| | - Lisa C. Krishnamurthy
- Center for Visual and Neurocognitive Rehabilitation, Atlanta VAMC, Decatur, GA, United States
- Department of Physics & Astronomy, Georgia State University, Atlanta, GA, United States
| | - Jolie D. Barter
- Division of Geriatrics and Gerontology, Department of Medicine, Emory University, Atlanta, GA, United States
| | - Aaminah Turabi
- Center for Visual and Neurocognitive Rehabilitation, Atlanta VAMC, Decatur, GA, United States
- Department of Biology, Georgia State University, Atlanta, GA, United States
| | - Ihab M. Hajjar
- Department of Neurology, Emory University, Atlanta, GA, United States
| | - Joe R. Nocera
- Center for Visual and Neurocognitive Rehabilitation, Atlanta VAMC, Decatur, GA, United States
- Department of Neurology, Emory University, Atlanta, GA, United States
- Division of Physical Therapy, Department of Rehabilitation Medicine, Emory University, Atlanta, GA, United States
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21
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Sleight E, Stringer MS, Marshall I, Wardlaw JM, Thrippleton MJ. Cerebrovascular Reactivity Measurement Using Magnetic Resonance Imaging: A Systematic Review. Front Physiol 2021; 12:643468. [PMID: 33716793 PMCID: PMC7947694 DOI: 10.3389/fphys.2021.643468] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 02/01/2021] [Indexed: 12/27/2022] Open
Abstract
Cerebrovascular reactivity (CVR) magnetic resonance imaging (MRI) probes cerebral haemodynamic changes in response to a vasodilatory stimulus. CVR closely relates to the health of the vasculature and is therefore a key parameter for studying cerebrovascular diseases such as stroke, small vessel disease and dementias. MRI allows in vivo measurement of CVR but several different methods have been presented in the literature, differing in pulse sequence, hardware requirements, stimulus and image processing technique. We systematically reviewed publications measuring CVR using MRI up to June 2020, identifying 235 relevant papers. We summarised the acquisition methods, experimental parameters, hardware and CVR quantification approaches used, clinical populations investigated, and corresponding summary CVR measures. CVR was investigated in many pathologies such as steno-occlusive diseases, dementia and small vessel disease and is generally lower in patients than in healthy controls. Blood oxygen level dependent (BOLD) acquisitions with fixed inspired CO2 gas or end-tidal CO2 forcing stimulus are the most commonly used methods. General linear modelling of the MRI signal with end-tidal CO2 as the regressor is the most frequently used method to compute CVR. Our survey of CVR measurement approaches and applications will help researchers to identify good practice and provide objective information to inform the development of future consensus recommendations.
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Affiliation(s)
- Emilie Sleight
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom,UK Dementia Research Institute, Edinburgh, United Kingdom
| | - Michael S. Stringer
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom,UK Dementia Research Institute, Edinburgh, United Kingdom,*Correspondence: Michael S. Stringer
| | - Ian Marshall
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom,UK Dementia Research Institute, Edinburgh, United Kingdom
| | - Joanna M. Wardlaw
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom,UK Dementia Research Institute, Edinburgh, United Kingdom
| | - Michael J. Thrippleton
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom,UK Dementia Research Institute, Edinburgh, United Kingdom
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22
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Hrybouski S, Cribben I, McGonigle J, Olsen F, Carter R, Seres P, Madan CR, Malykhin NV. Investigating the effects of healthy cognitive aging on brain functional connectivity using 4.7 T resting-state functional magnetic resonance imaging. Brain Struct Funct 2021; 226:1067-1098. [PMID: 33604746 DOI: 10.1007/s00429-021-02226-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 01/20/2021] [Indexed: 01/05/2023]
Abstract
Functional changes in the aging human brain have been previously reported using functional magnetic resonance imaging (fMRI). Earlier resting-state fMRI studies revealed an age-associated weakening of intra-system functional connectivity (FC) and age-associated strengthening of inter-system FC. However, the majority of such FC studies did not investigate the relationship between age and network amplitude, without which correlation-based measures of FC can be challenging to interpret. Consequently, the main aim of this study was to investigate how three primary measures of resting-state fMRI signal-network amplitude, network topography, and inter-network FC-are affected by healthy cognitive aging. We acquired resting-state fMRI data on a 4.7 T scanner for 105 healthy participants representing the entire adult lifespan (18-85 years of age). To study age differences in network structure, we combined ICA-based network decomposition with sparse graphical models. Older adults displayed lower blood-oxygen-level-dependent (BOLD) signal amplitude in all functional systems, with sensorimotor networks showing the largest age differences. Our age comparisons of network topography and inter-network FC demonstrated a substantial amount of age invariance in the brain's functional architecture. Despite architecture similarities, old adults displayed a loss of communication efficiency in our inter-network FC comparisons, driven primarily by the FC reduction in frontal and parietal association cortices. Together, our results provide a comprehensive overview of age effects on fMRI-based FC.
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Affiliation(s)
- Stanislau Hrybouski
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
| | - Ivor Cribben
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada.,Department of Accounting and Business Analytics, Alberta School of Business, University of Alberta, Edmonton, AB, Canada
| | - John McGonigle
- Department of Brain Sciences, Imperial College London, London, UK
| | - Fraser Olsen
- Department of Biomedical Engineering, University of Alberta, Edmonton, AB, Canada
| | - Rawle Carter
- Department of Psychiatry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, T6G 2V2, Canada
| | - Peter Seres
- Department of Biomedical Engineering, University of Alberta, Edmonton, AB, Canada
| | | | - Nikolai V Malykhin
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada. .,Department of Biomedical Engineering, University of Alberta, Edmonton, AB, Canada. .,Department of Psychiatry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, T6G 2V2, Canada.
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23
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Srokova S, Hill PF, Elward RL, Rugg MD. Effects of age on goal-dependent modulation of episodic memory retrieval. Neurobiol Aging 2021; 102:73-88. [PMID: 33765433 DOI: 10.1016/j.neurobiolaging.2021.02.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 02/02/2021] [Accepted: 02/03/2021] [Indexed: 10/22/2022]
Abstract
Retrieval gating refers to the ability to modulate the retrieval of features of a single memory episode according to behavioral goals. Recent findings demonstrate that younger adults engage retrieval gating by attenuating the representation of task-irrelevant features of an episode. Here, we examine whether retrieval gating varies with age. Younger and older adults incidentally encoded words superimposed over scenes or scrambled backgrounds that were displayed in one of three spatial locations. Participants subsequently underwent fMRI as they completed two memory tasks: the background task, which tested memory for the word's background, and the location task, testing memory for the word's location. Employing univariate and multivariate approaches, we demonstrated that younger, but not older adults, exhibited attenuated reinstatement of scene information when it was goal-irrelevant (during the location task). Additionally, in younger adults only, the strength of scene reinstatement in the parahippocampal place area during the background task was related to item and source memory performance. Together, these findings point to an age-related decline in the ability to engage retrieval gating.
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Affiliation(s)
- Sabina Srokova
- Center for Vital Longevity, University of Texas at Dallas, Dallas, TX, USA; School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, TX, USA.
| | - Paul F Hill
- Center for Vital Longevity, University of Texas at Dallas, Dallas, TX, USA; School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, TX, USA
| | - Rachael L Elward
- School of Applied Sciences, Division of Psychology, London South Bank University, London, UK
| | - Michael D Rugg
- Center for Vital Longevity, University of Texas at Dallas, Dallas, TX, USA; School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, TX, USA; School of Psychology, University of East Anglia, Norwich, UK; Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX, USA
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24
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Liu ES, Koen JD, Rugg MD. Effects of Age on Prestimulus Neural Activity Predictive of Successful Memory Encoding: An fMRI Study. Cereb Cortex 2021; 31:917-932. [PMID: 32959047 DOI: 10.1093/cercor/bhaa265] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 07/17/2020] [Accepted: 08/13/2020] [Indexed: 11/13/2022] Open
Abstract
Prestimulus subsequent memory effects (SMEs)-differences in neural activity preceding the onset of study items that are predictive of later memory performance-have consistently been reported in young adults. The present functional magnetic resonance imaging experiment investigated potential age-related differences in prestimulus SMEs. During study, healthy young and older participants made one of two semantic judgments on images, with the judgment signaled by a preceding cue. In test phase, participants first made an item recognition judgment and, for each item judged old, a source memory judgment. Age-invariant prestimulus SMEs were observed in left dorsomedial prefrontal cortex, left hippocampus, and right subgenual cortex. In each case, the effects reflected lower blood oxygen level dependent signal for later recognized items, regardless of source accuracy, than for unrecognized items. A similar age-invariant pattern was observed in left orbitofrontal cortex, but this effect was specific to items attracting a correct source response compared to unrecognized items. In contrast, the left angular gyrus and fusiform cortex demonstrated negative prestimulus SMEs that were exclusive to young participants. The findings indicate that age differences in prestimulus SMEs are regionally specific and suggest that prestimulus SMEs reflect multiple cognitive processes, only some of which are vulnerable to advancing age.
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Affiliation(s)
- E Song Liu
- Center for Vital Longevity, University of Texas at Dallas, Dallas, TX 75235, USA.,School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, TX 75080, USA
| | - Joshua D Koen
- Department of Psychology, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Michael D Rugg
- Center for Vital Longevity, University of Texas at Dallas, Dallas, TX 75235, USA.,School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, TX 75080, USA.,School of Psychology, University of East Anglia, Norwich NR4 7TJ, UK
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25
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Tsvetanov KA, Henson RNA, Rowe JB. Separating vascular and neuronal effects of age on fMRI BOLD signals. Philos Trans R Soc Lond B Biol Sci 2021; 376:20190631. [PMID: 33190597 PMCID: PMC7741031 DOI: 10.1098/rstb.2019.0631] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/19/2020] [Indexed: 12/14/2022] Open
Abstract
Accurate identification of brain function is necessary to understand the neurobiology of cognitive ageing, and thereby promote well-being across the lifespan. A common tool used to investigate neurocognitive ageing is functional magnetic resonance imaging (fMRI). However, although fMRI data are often interpreted in terms of neuronal activity, the blood oxygenation level-dependent (BOLD) signal measured by fMRI includes contributions of both vascular and neuronal factors, which change differentially with age. While some studies investigate vascular ageing factors, the results of these studies are not well known within the field of neurocognitive ageing and therefore vascular confounds in neurocognitive fMRI studies are common. Despite over 10 000 BOLD-fMRI papers on ageing, fewer than 20 have applied techniques to correct for vascular effects. However, neurovascular ageing is not only a confound in fMRI, but an important feature in its own right, to be assessed alongside measures of neuronal ageing. We review current approaches to dissociate neuronal and vascular components of BOLD-fMRI of regional activity and functional connectivity. We highlight emerging evidence that vascular mechanisms in the brain do not simply control blood flow to support the metabolic needs of neurons, but form complex neurovascular interactions that influence neuronal function in health and disease. This article is part of the theme issue 'Key relationships between non-invasive functional neuroimaging and the underlying neuronal activity'.
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Affiliation(s)
- Kamen A. Tsvetanov
- Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0SZ, UK
- Department of Psychology, University of Cambridge, Cambridge CB2 3EB, UK
| | - Richard N. A. Henson
- Department of Psychiatry, University of Cambridge, Cambridge CB2 0SP, UK
- Medical Research Council Cognition and Brain Sciences Unit, University of Cambridge, Cambridge CB2 7EF, UK
| | - James B. Rowe
- Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0SZ, UK
- Medical Research Council Cognition and Brain Sciences Unit, University of Cambridge, Cambridge CB2 7EF, UK
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26
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Eisenstein T, Yogev-Seligmann G, Ash E, Giladi N, Sharon H, Shapira-Lichter I, Nachman S, Hendler T, Lerner Y. Maximal aerobic capacity is associated with hippocampal cognitive reserve in older adults with amnestic mild cognitive impairment. Hippocampus 2020; 31:305-320. [PMID: 33314497 DOI: 10.1002/hipo.23290] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 09/03/2020] [Accepted: 11/28/2020] [Indexed: 01/03/2023]
Abstract
Maximal aerobic capacity (MAC) has been associated with preserved neural tissue or brain maintenance (BM) in healthy older adults, including the hippocampus. Amnestic mild cognitive impairment (aMCI) is considered a prodromal stage of Alzheimer's disease. While aMCI is characterized by hippocampal deterioration, the MAC-hippocampal relationship in these patients is not well understood. In contrast to healthy individuals, neurocognitive protective effects in neurodegenerative populations have been associated with mechanisms of cognitive reserve (CR) altering the neuropathology-cognition relationship. We investigated the MAC-hippocampal relationship in aMCI (n = 29) from the perspectives of BM and CR mechanistic models with structural MRI and a memory fMRI paradigm using both group-level (higher-fit patients vs. lower-fit patients) and individual level (continuous correlation) approaches. While MAC was associated with smaller hippocampal volume, contradicting the BM model, higher-fit patients demonstrated statistically significant lower correlation between hippocampal volume and memory performance compared with the lower-fit patients, supporting the model of CR. In addition, while there was no difference in brain activity between the groups during low cognitive demand (encoding of familiar stimuli), higher MAC level was associated with increased cortical and sub-cortical activation during increased cognitive demand (encoding of novel stimuli) and also with bilateral hippocampal activity even when controlling for hippocampal volume, suggesting for an independent effect of MAC. Our results suggest that MAC may be associated with hippocampal-related cognitive reserve in aMCI through altering the relationship between hippocampal-related structural deterioration and cognitive function. In addition, MAC was found to be associated with increased capacity to recruit neural resources during increased cognitive demands.
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Affiliation(s)
- Tamir Eisenstein
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.,Sagol Brain Institute, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
| | - Galit Yogev-Seligmann
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.,Sagol Brain Institute, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
| | - Elissa Ash
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.,Department of Neurology, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
| | - Nir Giladi
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.,Department of Neurology, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel.,Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Haggai Sharon
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.,Sagol Brain Institute, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel.,Pain Management & Neuromodulation Centre, Guy's & St Thomas' NHS Foundation Trust, London, UK.,Institute of Pain Medicine, Department of Anesthesiology and Critical Care Medicine, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
| | - Irit Shapira-Lichter
- Functional MRI Center, Beilinson Hospital, Rabin Medical Center, Petah Tikva, Israel
| | - Shikma Nachman
- Sagol Brain Institute, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
| | - Talma Hendler
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.,Sagol Brain Institute, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel.,Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel.,School of Psychological Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Yulia Lerner
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.,Sagol Brain Institute, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel.,Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
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27
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Hou M, de Chastelaine M, Jayakumar M, Donley BE, Rugg MD. Recollection-related hippocampal fMRI effects predict longitudinal memory change in healthy older adults. Neuropsychologia 2020; 146:107537. [PMID: 32569610 DOI: 10.1016/j.neuropsychologia.2020.107537] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 06/11/2020] [Accepted: 06/12/2020] [Indexed: 02/07/2023]
Abstract
Prior fMRI studies have reported relationships between memory-related activity in the hippocampus and in-scanner memory performance, but whether such activity is predictive of longitudinal memory change remains unclear. Here, we administered a neuropsychological test battery to a sample of cognitively healthy older adults on three occasions, the second and third sessions occurring one month and three years after the first session. Structural and functional MRI data were acquired between the first two sessions. The fMRI data were derived from an associative recognition procedure and allowed estimation of hippocampal effects associated with both successful associative encoding and successful associative recognition (recollection). Baseline memory performance and memory change were evaluated using memory component scores derived from a principal components analysis of the neuropsychological test scores. Across participants, right hippocampal encoding effects correlated significantly with baseline memory performance after controlling for chronological age. Additionally, both left and right hippocampal associative recognition effects correlated negatively with longitudinal memory decline after controlling for age, and the relationship with the left hippocampal effect remained after also controlling for left hippocampal volume. Thus, in cognitively healthy older adults, the magnitude of hippocampal recollection effects appears to be a robust predictor of future memory change.
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Affiliation(s)
- Mingzhu Hou
- Center for Vital Longevity and School of Behavioral and Brain Sciences, The University of Texas at Dallas, Dallas, TX, 75235, USA.
| | - Marianne de Chastelaine
- Center for Vital Longevity and School of Behavioral and Brain Sciences, The University of Texas at Dallas, Dallas, TX, 75235, USA
| | - Manasi Jayakumar
- Center for Vital Longevity and School of Behavioral and Brain Sciences, The University of Texas at Dallas, Dallas, TX, 75235, USA
| | - Brian E Donley
- Center for Vital Longevity and School of Behavioral and Brain Sciences, The University of Texas at Dallas, Dallas, TX, 75235, USA
| | - Michael D Rugg
- Center for Vital Longevity and School of Behavioral and Brain Sciences, The University of Texas at Dallas, Dallas, TX, 75235, USA; School of Psychology, University of East Anglia, Norwich, NR4 7TJ, UK
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28
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Blair GW, Thrippleton MJ, Shi Y, Hamilton I, Stringer M, Chappell F, Dickie DA, Andrews P, Marshall I, Doubal FN, Wardlaw JM. Intracranial hemodynamic relationships in patients with cerebral small vessel disease. Neurology 2020; 94:e2258-e2269. [PMID: 32366534 PMCID: PMC7357294 DOI: 10.1212/wnl.0000000000009483] [Citation(s) in RCA: 83] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Accepted: 12/10/2019] [Indexed: 02/06/2023] Open
Abstract
Objective To investigate cerebrovascular reactivity (CVR), blood flow, vascular and CSF pulsatility, and their independent relationship with cerebral small vessel disease (SVD) features in patients with minor ischemic stroke and MRI evidence of SVD. Methods We recruited patients with minor ischemic stroke and assessed CVR using blood oxygen level–dependent MRI during a hypercapnic challenge, cerebral blood flow (CBF), vascular and CSF pulsatility using phase-contrast MRI, and structural magnetic resonance brain imaging to quantify white matter hyperintensities (WMHs) and perivascular spaces (PVSs). We used multiple regression to identify parameters associated with SVD features, controlling for patient characteristics. Results Fifty-three of 60 patients completed the study with a full data set (age 68.0% ± 8.8 years, 74% male, 75% hypertensive). After controlling for age, sex, and systolic blood pressure, lower white matter CVR was associated with higher WMH volume (−0.01%/mm Hg per log10 increase in WMH volume, p = 0.02), basal ganglia PVS (−0.01%/mm Hg per point increase in the PVS score, p = 0.02), and higher venous pulsatility (superior sagittal sinus −0.03%/mm Hg, p = 0.02, per unit increase in the pulsatility index) but not with CBF (p = 0.58). Lower foramen magnum CSF stroke volume was associated with worse white matter CVR (0.04%/mm Hg per mL increase in stroke volume, p = 0.04) and more severe basal ganglia PVS (p = 0.09). Conclusions Lower CVR, higher venous pulsatility, and lower foramen magnum CSF stroke volume indicate that dynamic vascular dysfunctions underpin PVS dysfunction and WMH development. Further exploration of microvascular dysfunction and CSF dynamics may uncover new mechanisms and intervention targets to reduce SVD lesion development, cognitive decline, and stroke.
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Affiliation(s)
- Gordon W Blair
- From the Brain Research Imaging Centre (G.W.B., M.J.T., Y.S., I.H., M.S., F.C., P.A., I.M., F.N.D., J.M.W.), Centre for Clinical Brain Sciences, University of Edinburgh, United Kingdom; UK Dementia Research Institute at The University of Edinburgh (G.W.B., M.J.T., Y.S., I.H., M.S., F.N.D., J.M.W.), Edinburgh Medical School, United Kingdom; Beijing Tiantan Hospital Affiliated to Capital Medical University (Y.S.), China; Institute of Cardiovascular and Medical Sciences (D.A.D.), University of Glasgow, United Kingdom; and Centre for Cognitive Ageing and Cognitive Epidemiology (J.M.W.), University of Edinburgh, United Kingdom
| | - Michael J Thrippleton
- From the Brain Research Imaging Centre (G.W.B., M.J.T., Y.S., I.H., M.S., F.C., P.A., I.M., F.N.D., J.M.W.), Centre for Clinical Brain Sciences, University of Edinburgh, United Kingdom; UK Dementia Research Institute at The University of Edinburgh (G.W.B., M.J.T., Y.S., I.H., M.S., F.N.D., J.M.W.), Edinburgh Medical School, United Kingdom; Beijing Tiantan Hospital Affiliated to Capital Medical University (Y.S.), China; Institute of Cardiovascular and Medical Sciences (D.A.D.), University of Glasgow, United Kingdom; and Centre for Cognitive Ageing and Cognitive Epidemiology (J.M.W.), University of Edinburgh, United Kingdom
| | - Yulu Shi
- From the Brain Research Imaging Centre (G.W.B., M.J.T., Y.S., I.H., M.S., F.C., P.A., I.M., F.N.D., J.M.W.), Centre for Clinical Brain Sciences, University of Edinburgh, United Kingdom; UK Dementia Research Institute at The University of Edinburgh (G.W.B., M.J.T., Y.S., I.H., M.S., F.N.D., J.M.W.), Edinburgh Medical School, United Kingdom; Beijing Tiantan Hospital Affiliated to Capital Medical University (Y.S.), China; Institute of Cardiovascular and Medical Sciences (D.A.D.), University of Glasgow, United Kingdom; and Centre for Cognitive Ageing and Cognitive Epidemiology (J.M.W.), University of Edinburgh, United Kingdom
| | - Iona Hamilton
- From the Brain Research Imaging Centre (G.W.B., M.J.T., Y.S., I.H., M.S., F.C., P.A., I.M., F.N.D., J.M.W.), Centre for Clinical Brain Sciences, University of Edinburgh, United Kingdom; UK Dementia Research Institute at The University of Edinburgh (G.W.B., M.J.T., Y.S., I.H., M.S., F.N.D., J.M.W.), Edinburgh Medical School, United Kingdom; Beijing Tiantan Hospital Affiliated to Capital Medical University (Y.S.), China; Institute of Cardiovascular and Medical Sciences (D.A.D.), University of Glasgow, United Kingdom; and Centre for Cognitive Ageing and Cognitive Epidemiology (J.M.W.), University of Edinburgh, United Kingdom
| | - Michael Stringer
- From the Brain Research Imaging Centre (G.W.B., M.J.T., Y.S., I.H., M.S., F.C., P.A., I.M., F.N.D., J.M.W.), Centre for Clinical Brain Sciences, University of Edinburgh, United Kingdom; UK Dementia Research Institute at The University of Edinburgh (G.W.B., M.J.T., Y.S., I.H., M.S., F.N.D., J.M.W.), Edinburgh Medical School, United Kingdom; Beijing Tiantan Hospital Affiliated to Capital Medical University (Y.S.), China; Institute of Cardiovascular and Medical Sciences (D.A.D.), University of Glasgow, United Kingdom; and Centre for Cognitive Ageing and Cognitive Epidemiology (J.M.W.), University of Edinburgh, United Kingdom
| | - Francesca Chappell
- From the Brain Research Imaging Centre (G.W.B., M.J.T., Y.S., I.H., M.S., F.C., P.A., I.M., F.N.D., J.M.W.), Centre for Clinical Brain Sciences, University of Edinburgh, United Kingdom; UK Dementia Research Institute at The University of Edinburgh (G.W.B., M.J.T., Y.S., I.H., M.S., F.N.D., J.M.W.), Edinburgh Medical School, United Kingdom; Beijing Tiantan Hospital Affiliated to Capital Medical University (Y.S.), China; Institute of Cardiovascular and Medical Sciences (D.A.D.), University of Glasgow, United Kingdom; and Centre for Cognitive Ageing and Cognitive Epidemiology (J.M.W.), University of Edinburgh, United Kingdom
| | - David Alexander Dickie
- From the Brain Research Imaging Centre (G.W.B., M.J.T., Y.S., I.H., M.S., F.C., P.A., I.M., F.N.D., J.M.W.), Centre for Clinical Brain Sciences, University of Edinburgh, United Kingdom; UK Dementia Research Institute at The University of Edinburgh (G.W.B., M.J.T., Y.S., I.H., M.S., F.N.D., J.M.W.), Edinburgh Medical School, United Kingdom; Beijing Tiantan Hospital Affiliated to Capital Medical University (Y.S.), China; Institute of Cardiovascular and Medical Sciences (D.A.D.), University of Glasgow, United Kingdom; and Centre for Cognitive Ageing and Cognitive Epidemiology (J.M.W.), University of Edinburgh, United Kingdom
| | - Peter Andrews
- From the Brain Research Imaging Centre (G.W.B., M.J.T., Y.S., I.H., M.S., F.C., P.A., I.M., F.N.D., J.M.W.), Centre for Clinical Brain Sciences, University of Edinburgh, United Kingdom; UK Dementia Research Institute at The University of Edinburgh (G.W.B., M.J.T., Y.S., I.H., M.S., F.N.D., J.M.W.), Edinburgh Medical School, United Kingdom; Beijing Tiantan Hospital Affiliated to Capital Medical University (Y.S.), China; Institute of Cardiovascular and Medical Sciences (D.A.D.), University of Glasgow, United Kingdom; and Centre for Cognitive Ageing and Cognitive Epidemiology (J.M.W.), University of Edinburgh, United Kingdom
| | - Ian Marshall
- From the Brain Research Imaging Centre (G.W.B., M.J.T., Y.S., I.H., M.S., F.C., P.A., I.M., F.N.D., J.M.W.), Centre for Clinical Brain Sciences, University of Edinburgh, United Kingdom; UK Dementia Research Institute at The University of Edinburgh (G.W.B., M.J.T., Y.S., I.H., M.S., F.N.D., J.M.W.), Edinburgh Medical School, United Kingdom; Beijing Tiantan Hospital Affiliated to Capital Medical University (Y.S.), China; Institute of Cardiovascular and Medical Sciences (D.A.D.), University of Glasgow, United Kingdom; and Centre for Cognitive Ageing and Cognitive Epidemiology (J.M.W.), University of Edinburgh, United Kingdom
| | - Fergus N Doubal
- From the Brain Research Imaging Centre (G.W.B., M.J.T., Y.S., I.H., M.S., F.C., P.A., I.M., F.N.D., J.M.W.), Centre for Clinical Brain Sciences, University of Edinburgh, United Kingdom; UK Dementia Research Institute at The University of Edinburgh (G.W.B., M.J.T., Y.S., I.H., M.S., F.N.D., J.M.W.), Edinburgh Medical School, United Kingdom; Beijing Tiantan Hospital Affiliated to Capital Medical University (Y.S.), China; Institute of Cardiovascular and Medical Sciences (D.A.D.), University of Glasgow, United Kingdom; and Centre for Cognitive Ageing and Cognitive Epidemiology (J.M.W.), University of Edinburgh, United Kingdom
| | - Joanna M Wardlaw
- From the Brain Research Imaging Centre (G.W.B., M.J.T., Y.S., I.H., M.S., F.C., P.A., I.M., F.N.D., J.M.W.), Centre for Clinical Brain Sciences, University of Edinburgh, United Kingdom; UK Dementia Research Institute at The University of Edinburgh (G.W.B., M.J.T., Y.S., I.H., M.S., F.N.D., J.M.W.), Edinburgh Medical School, United Kingdom; Beijing Tiantan Hospital Affiliated to Capital Medical University (Y.S.), China; Institute of Cardiovascular and Medical Sciences (D.A.D.), University of Glasgow, United Kingdom; and Centre for Cognitive Ageing and Cognitive Epidemiology (J.M.W.), University of Edinburgh, United Kingdom.
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29
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Krishnamurthy V, Krishnamurthy LC, Drucker JH, Kundu S, Ji B, Hortman K, Roberts SR, Mammino K, Tran SM, Gopinath K, McGregor KM, Rodriguez AD, Qiu D, Crosson B, Nocera JR. Correcting Task fMRI Signals for Variability in Baseline CBF Improves BOLD-Behavior Relationships: A Feasibility Study in an Aging Model. Front Neurosci 2020; 14:336. [PMID: 32425745 PMCID: PMC7205008 DOI: 10.3389/fnins.2020.00336] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 03/20/2020] [Indexed: 12/24/2022] Open
Abstract
Blood Oxygen Level Dependent (BOLD) functional MRI is a complex neurovascular signal whose magnitude depends on baseline physiological factors such as cerebral blood flow (CBF). Because baseline CBF varies across the brain and is altered with aging, the interpretation of stand-alone aging-related BOLD changes can be misleading. The primary objective of this study was to develop a methodology that combines task fMRI and arterial spin labeling (ASL) techniques to sensitize task-induced BOLD activity by covarying out the baseline physiology (i.e., CBF) in an aging model. We recruited 11 younger and 13 older healthy participants who underwent ASL and an overt language fMRI task (semantic category member generation). We measured in-scanner language performance to investigate the effect of BOLD sensitization on BOLD-behavior relationships. The results demonstrate that our correction approach is effective at enhancing the specificity and sensitivity of the BOLD signal in both groups. In addition, the correction strengthens the statistical association between task BOLD activity and behavioral performance. Although CBF has inherent age dependence, our results show that retaining the age factor within CBF aides in greater sensitization of task fMRI signals. From a cognitive standpoint, compared to young adults, the older participants showed a delayed domain-general language-related task activity possibly due to compromised vessel compliance. Further, assessment of functional evolution of corrected BOLD activity revealed biphasic BOLD dynamics in both groups where BOLD deactivation may reflect greater semantic demand or increased premium on domain general executive functioning in response to task difficulty. Although it was promising to note that the predictability of behavior using the proposed methodology outperforms other methodologies (i.e., no correction and normalization by division), and provides moderate stability and adequate power, further work with a larger cohort and other task designs is necessary to improve the stability of predicting associated behavior. In summary, we recommend correction of task fMRI signals by covarying out baseline CBF especially when comparing groups with different neurovascular properties. Given that ASL and BOLD fMRI are well established and widely employed techniques, our proposed multi-modal methodology can be readily implemented into data processing pipelines to obtain more accurate BOLD activation maps.
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Affiliation(s)
- Venkatagiri Krishnamurthy
- Department of Neurology, Emory University, Atlanta, GA, United States.,Center for Visual and Neurocognitive Rehabilitation, Atlanta Veterans Affairs Medical Center (VAMC), Decatur, GA, United States
| | - Lisa C Krishnamurthy
- Center for Visual and Neurocognitive Rehabilitation, Atlanta Veterans Affairs Medical Center (VAMC), Decatur, GA, United States.,Department of Physics and Astronomy, Georgia State University, Atlanta, GA, United States
| | - Jonathan H Drucker
- Department of Neurology, Emory University, Atlanta, GA, United States.,Center for Visual and Neurocognitive Rehabilitation, Atlanta Veterans Affairs Medical Center (VAMC), Decatur, GA, United States
| | - Suprateek Kundu
- Department of Biostatistics and Bioinformatics, Emory University, Atlanta, GA, United States
| | - Bing Ji
- Department of Neurology, Emory University, Atlanta, GA, United States.,Center for Visual and Neurocognitive Rehabilitation, Atlanta Veterans Affairs Medical Center (VAMC), Decatur, GA, United States.,Department of Radiology and Imaging Sciences, Emory University, Atlanta, GA, United States
| | - Kyle Hortman
- Center for Visual and Neurocognitive Rehabilitation, Atlanta Veterans Affairs Medical Center (VAMC), Decatur, GA, United States
| | - Simone R Roberts
- Department of Neurology, Emory University, Atlanta, GA, United States.,Center for Visual and Neurocognitive Rehabilitation, Atlanta Veterans Affairs Medical Center (VAMC), Decatur, GA, United States.,Department of Psychology, Georgia State University, Atlanta, GA, United States
| | - Kevin Mammino
- Center for Visual and Neurocognitive Rehabilitation, Atlanta Veterans Affairs Medical Center (VAMC), Decatur, GA, United States
| | - Stella M Tran
- Department of Psychology, Georgia State University, Atlanta, GA, United States
| | - Kaundinya Gopinath
- Department of Radiology and Imaging Sciences, Emory University, Atlanta, GA, United States
| | - Keith M McGregor
- Department of Neurology, Emory University, Atlanta, GA, United States.,Center for Visual and Neurocognitive Rehabilitation, Atlanta Veterans Affairs Medical Center (VAMC), Decatur, GA, United States
| | - Amy D Rodriguez
- Department of Neurology, Emory University, Atlanta, GA, United States.,Center for Visual and Neurocognitive Rehabilitation, Atlanta Veterans Affairs Medical Center (VAMC), Decatur, GA, United States
| | - Deqiang Qiu
- Department of Radiology and Imaging Sciences, Emory University, Atlanta, GA, United States
| | - Bruce Crosson
- Department of Neurology, Emory University, Atlanta, GA, United States.,Center for Visual and Neurocognitive Rehabilitation, Atlanta Veterans Affairs Medical Center (VAMC), Decatur, GA, United States.,Department of Psychology, Georgia State University, Atlanta, GA, United States
| | - Joe R Nocera
- Department of Neurology, Emory University, Atlanta, GA, United States.,Center for Visual and Neurocognitive Rehabilitation, Atlanta Veterans Affairs Medical Center (VAMC), Decatur, GA, United States.,Division of Physical Therapy, School of Medicine, Emory University, Atlanta, GA, United States
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30
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Liu P, Xu C, Lin Z, Sur S, Li Y, Yasar S, Rosenberg P, Albert M, Lu H. Cerebrovascular reactivity mapping using intermittent breath modulation. Neuroimage 2020; 215:116787. [PMID: 32278094 DOI: 10.1016/j.neuroimage.2020.116787] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 03/24/2020] [Accepted: 03/30/2020] [Indexed: 01/28/2023] Open
Abstract
Cerebrovascular reactivity (CVR), an index of brain vessel's dilatory capacity, is typically measured using hypercapnic gas inhalation or breath-holding as a vasoactive challenge. However, these methods require considerable subject cooperation and could be challenging in clinical studies. More recently, there have been attempts to use resting-state BOLD data to map CVR by utilizing spontaneous changes in breathing pattern. However, in subjects who have small fluctuations in their spontaneous breathing pattern, the CVR results could be noisy and unreliable. In this study, we aim to develop a new method for CVR mapping that does not require gas-inhalation yet provides substantially higher sensitivity than resting-state CVR mapping. This new method is largely based on resting-state scan, but introduces intermittent modulation of breathing pattern in the subject to enhance fluctuations in their end-tidal CO2 (EtCO2) level. Here we examined the comfort level, sensitivity, and accuracy of this method in two studies. First, in 8 healthy young subjects, we developed the intermittent breath-modulation method using two different modulation frequencies, 6 s per breath and 12 s per breath, respectively, and compared the results to three existing CVR methods, specifically hypercapnic gas inhalation, breath-holding, and resting-state. Our results showed that the comfort level of the 6-s breath-modulation method was significantly higher than breath-holding (p = 0.007) and CO2-inhalation (p = 0.015) methods, while not different from the resting-state, i.e. free breathing method (p = 0.52). When comparing the sensitivity of CVR methods, the breath-modulation methods revealed higher Z-statistics compared to the resting-state scan (p < 0.008) and was comparable to breath-holding results. Next, we tested the feasibility of breath-modulation CVR mapping (6 s per breath) in 21 cognitively normal elderly participants and compared quantitative CVR values to that obtained with the CO2-inhalation method. Whole-brain CVR was found to be 0.150 ± 0.055 and 0.154 ± 0.032 %ΔBOLD/mmHg for the breath-modulation and CO2-inhalation method, respectively, with a significant correlation between them (y = 0.97x, p = 0.007). CVR mapping with intermittent breath modulation may be a useful method that combines the advantages of resting-state and CO2-inhalation based approaches.
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Affiliation(s)
- Peiying Liu
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| | - Cuimei Xu
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Zixuan Lin
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Sandeepa Sur
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Yang Li
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Sevil Yasar
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Paul Rosenberg
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Marilyn Albert
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Hanzhang Lu
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, MD, USA
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31
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Liang X, Hsu LM, Lu H, Ash JA, Rapp PR, Yang Y. Functional Connectivity of Hippocampal CA3 Predicts Neurocognitive Aging via CA1-Frontal Circuit. Cereb Cortex 2020; 30:4297-4305. [PMID: 32239141 DOI: 10.1093/cercor/bhaa008] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 12/08/2019] [Accepted: 01/08/2020] [Indexed: 01/06/2023] Open
Abstract
The CA3 and CA1 principal cell fields of the hippocampus are vulnerable to aging, and age-related dysfunction in CA3 may be an early seed event closely linked to individual differences in memory decline. However, whether the differential vulnerability of CA3 and CA1 is associated with broader disruption in network-level functional interactions in relation to age-related memory impairment, and more specifically, whether CA3 dysconnectivity contributes to the effects of aging via CA1 network connectivity, has been difficult to test. Here, using resting-state fMRI in a group of aged rats uncontaminated by neurodegenerative disease, aged rats displayed widespread reductions in functional connectivity of CA3 and CA1 fields. Age-related memory deficits were predicted by connectivity between left CA3 and hippocampal circuitry along with connectivity between left CA1 and infralimbic prefrontal cortex. Notably, the effects of CA3 connectivity on memory performance were mediated by CA1 connectivity with prefrontal cortex. We additionally found that spatial learning and memory were associated with functional connectivity changes lateralized to the left CA3 and CA1 divisions. These results provide novel evidence that network-level dysfunction involving interactions of CA3 with CA1 is an early marker of poor cognitive outcome in aging.
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Affiliation(s)
- Xia Liang
- Laboratory for Space Environment and Physical Sciences, Harbin Institute of Technology, Harbin 150001, China.,Neuroimaging Research Branch, National Institute on Drug Abuse, Biomedical Research Center, National Institutes of Health (NIH), Baltimore, MD 21224, USA
| | - Li-Ming Hsu
- Neuroimaging Research Branch, National Institute on Drug Abuse, Biomedical Research Center, National Institutes of Health (NIH), Baltimore, MD 21224, USA.,Department of Radiology and Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Hanbing Lu
- Neuroimaging Research Branch, National Institute on Drug Abuse, Biomedical Research Center, National Institutes of Health (NIH), Baltimore, MD 21224, USA
| | - Jessica A Ash
- Laboratory of Behavioral Neuroscience, National Institute on Aging, Biomedical Research Center, NIH, Baltimore, MD 21224, USA
| | - Peter R Rapp
- Laboratory of Behavioral Neuroscience, National Institute on Aging, Biomedical Research Center, NIH, Baltimore, MD 21224, USA
| | - Yihong Yang
- Neuroimaging Research Branch, National Institute on Drug Abuse, Biomedical Research Center, National Institutes of Health (NIH), Baltimore, MD 21224, USA
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32
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Tucker WJ, Thomas BP, Puzziferri N, Samuel TJ, Zaha VG, Lingvay I, Almandoz J, Wang J, Gonzales EA, Brothers RM, Nelson MD. Impact of bariatric surgery on cerebral vascular reactivity and cognitive function: a non-randomized pilot study. Pilot Feasibility Stud 2020; 6:21. [PMID: 32082607 PMCID: PMC7017515 DOI: 10.1186/s40814-020-00569-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Accepted: 02/06/2020] [Indexed: 01/03/2023] Open
Abstract
Background Bariatric surgery is an effective long-term weight loss strategy yielding improvements in neurocognitive function; however, the mechanism(s) responsible for these improvements remains unclear. Here, we assessed the feasibility of using magnetic resonance imaging (MRI) to evaluate whether cerebral vascular reactivity (CVR) is impaired in severely obese bariatric surgery candidates compared with normal weight healthy controls and whether CVR improves following bariatric surgery. We also investigated whether changes in CVR were associated with changes in cognitive function. Methods Bariatric surgery candidates (n = 6) were compared with normal weight healthy controls of a similar age (n = 10) at baseline, and then reassessed 2 weeks and 14 weeks following sleeve gastrectomy bariatric surgery. Young reference controls (n = 7) were also studied at baseline to establish the range of normal for each outcome measure. Microvascular and macrovascular CVR to hypercapnia (5% CO2) were assessed using blood-oxygen-level-dependent (BOLD) MRI, and changes in the middle cerebral artery (MCA) cross-sectional area, respectively. Cognitive function was assessed using a validated neurocognitive software. Results Compliance with the CVR protocol was high. Both macro- and micro-cerebrovascular function were highest in the young reference controls. Cognitive function was lower in obese bariatric surgery candidates compared with normal weight controls, and improved by 17% at 2 weeks and 21% by 14 weeks following bariatric surgery. To our surprise, whole-brain CVR BOLD did not differ between obese bariatric surgery candidates and normal weight controls of similar age (0.184 ± 0.101 vs. 0.192 ± 0.034 %BOLD/mmHgCO2), and did not change after bariatric surgery. In contrast, we observed vasoconstriction of the MCA during hypercapnia in 60% of the obese patients prior to surgery, which appeared to be abolished following bariatric surgery. Improvements in cognitive function were not associated with improvements in either CVR BOLD or MCA vasodilation after bariatric surgery. Conclusions Assessing CVR responses to a hypercapnic challenge with MRI was feasible in severely obese bariatric patients. However, no changes in whole-brain BOLD CVR were observed following bariatric surgery despite improvements in cognitive function. We recommend that future large trials assess CVR responses to cognitive tasks (rather than hypercapnia) to better define the mechanisms responsible for cognitive function improvements following bariatric surgery.
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Affiliation(s)
- Wesley J Tucker
- 1Applied Physiology and Advanced Imaging Laboratory, Department of Kinesiology, University of Texas at Arlington, Science & Engineering Innovation & Research Building, 701 S. Nedderman Drive, Room 105, Arlington, TX 76019 USA.,2Department of Nutrition & Food Sciences, Texas Woman's University, Houston, TX USA
| | - Binu P Thomas
- 3Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX USA.,4Department of Bioengineering, University of Texas at Arlington, Arlington, TX USA
| | - Nancy Puzziferri
- 5Department of Surgery, Oregon Health & Science University, Portland, OR USA
| | - T Jake Samuel
- 1Applied Physiology and Advanced Imaging Laboratory, Department of Kinesiology, University of Texas at Arlington, Science & Engineering Innovation & Research Building, 701 S. Nedderman Drive, Room 105, Arlington, TX 76019 USA
| | - Vlad G Zaha
- 3Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX USA.,6Division of Cardiology, University of Texas Southwestern Medical Center, Dallas, TX USA
| | - Ildiko Lingvay
- 7Division of Endocrinology, Diabetes, and Metabolism, University of Texas Southwestern Medical Center, Dallas, TX USA
| | - Jaime Almandoz
- 7Division of Endocrinology, Diabetes, and Metabolism, University of Texas Southwestern Medical Center, Dallas, TX USA
| | - Jing Wang
- 8College of Nursing and Health Innovation, University of Texas at Arlington, Arlington, TX USA
| | - Edward A Gonzales
- 1Applied Physiology and Advanced Imaging Laboratory, Department of Kinesiology, University of Texas at Arlington, Science & Engineering Innovation & Research Building, 701 S. Nedderman Drive, Room 105, Arlington, TX 76019 USA.,8College of Nursing and Health Innovation, University of Texas at Arlington, Arlington, TX USA
| | - R Matthew Brothers
- 1Applied Physiology and Advanced Imaging Laboratory, Department of Kinesiology, University of Texas at Arlington, Science & Engineering Innovation & Research Building, 701 S. Nedderman Drive, Room 105, Arlington, TX 76019 USA
| | - Michael D Nelson
- 1Applied Physiology and Advanced Imaging Laboratory, Department of Kinesiology, University of Texas at Arlington, Science & Engineering Innovation & Research Building, 701 S. Nedderman Drive, Room 105, Arlington, TX 76019 USA.,4Department of Bioengineering, University of Texas at Arlington, Arlington, TX USA
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33
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Abdelkarim D, Zhao Y, Turner MP, Sivakolundu DK, Lu H, Rypma B. A neural-vascular complex of age-related changes in the human brain: Anatomy, physiology, and implications for neurocognitive aging. Neurosci Biobehav Rev 2019; 107:927-944. [DOI: 10.1016/j.neubiorev.2019.09.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 08/02/2019] [Accepted: 09/02/2019] [Indexed: 01/09/2023]
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34
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Subramaniapillai S, Rajagopal S, Elshiekh A, Pasvanis S, Ankudowich E, Rajah MN. Sex Differences in the Neural Correlates of Spatial Context Memory Decline in Healthy Aging. J Cogn Neurosci 2019; 31:1895-1916. [DOI: 10.1162/jocn_a_01455] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Aging is associated with episodic memory decline and alterations in memory-related brain function. However, it remains unclear if age-related memory decline is associated with similar patterns of brain aging in women and men. In the current task fMRI study, we tested the hypothesis that there are sex differences in the effect of age and memory performance on brain activity during episodic encoding and retrieval of face–location associations (spatial context memory). Forty-one women and 41 men between the ages of 21 and 76 years participated in this study. Between-group multivariate partial least squares analysis of the fMRI data was conducted to directly test for sex differences and similarities in age-related and performance-related patterns of brain activity. Our behavioral analysis indicated no significant sex differences in retrieval accuracy on the fMRI tasks. In relation to performance effects, we observed similarities and differences in how retrieval accuracy related to brain activity in women and men. Both sexes activated dorsal and lateral PFC, inferior parietal cortex, and left parahippocampal gyrus at encoding, and this supported subsequent memory performance. However, there were sex differences in retrieval activity in these same regions and in lateral occipital-temporal and ventrolateral PFC. In relation to age effects, we observed sex differences in the effect of age on memory-related activity within PFC, inferior parietal cortex, parahippocampal gyrus, and lateral occipital-temporal cortices. Overall, our findings suggest that the neural correlates of age-related spatial context memory decline differ in women compared with men.
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Affiliation(s)
| | | | | | | | | | - M. Natasha Rajah
- McGill University
- Brain Imaging Centre, Douglas Institute Research Centre, Verdun, QC, Canada
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35
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Kumral D, Şansal F, Cesnaite E, Mahjoory K, Al E, Gaebler M, Nikulin VV, Villringer A. BOLD and EEG signal variability at rest differently relate to aging in the human brain. Neuroimage 2019; 207:116373. [PMID: 31759114 DOI: 10.1016/j.neuroimage.2019.116373] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Revised: 10/17/2019] [Accepted: 11/17/2019] [Indexed: 01/22/2023] Open
Abstract
Variability of neural activity is regarded as a crucial feature of healthy brain function, and several neuroimaging approaches have been employed to assess it noninvasively. Studies on the variability of both evoked brain response and spontaneous brain signals have shown remarkable changes with aging but it is unclear if the different measures of brain signal variability - identified with either hemodynamic or electrophysiological methods - reflect the same underlying physiology. In this study, we aimed to explore age differences of spontaneous brain signal variability with two different imaging modalities (EEG, fMRI) in healthy younger (25 ± 3 years, N = 135) and older (67 ± 4 years, N = 54) adults. Consistent with the previous studies, we found lower blood oxygenation level dependent (BOLD) variability in the older subjects as well as less signal variability in the amplitude of low-frequency oscillations (1-12 Hz), measured in source space. These age-related reductions were mostly observed in the areas that overlap with the default mode network. Moreover, age-related increases of variability in the amplitude of beta-band frequency EEG oscillations (15-25 Hz) were seen predominantly in temporal brain regions. There were significant sex differences in EEG signal variability in various brain regions while no significant sex differences were observed in BOLD signal variability. Bivariate and multivariate correlation analyses revealed no significant associations between EEG- and fMRI-based variability measures. In summary, we show that both BOLD and EEG signal variability reflect aging-related processes but are likely to be dominated by different physiological origins, which relate differentially to age and sex.
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Affiliation(s)
- D Kumral
- Department of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany; MindBrainBody Institute at the Berlin School of Mind and Brain, Humboldt-Universität zu Berlin, Berlin, Germany.
| | - F Şansal
- International Graduate Program Medical Neurosciences, Charité-Universitätsmedizin, Berlin, Germany; Department of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - E Cesnaite
- Department of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - K Mahjoory
- Department of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany; Institute for Biomagnetism and Biosignalanalysis, University of Muenster, Muenster, Germany
| | - E Al
- MindBrainBody Institute at the Berlin School of Mind and Brain, Humboldt-Universität zu Berlin, Berlin, Germany; Department of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - M Gaebler
- Department of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany; MindBrainBody Institute at the Berlin School of Mind and Brain, Humboldt-Universität zu Berlin, Berlin, Germany
| | - V V Nikulin
- Department of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany; Neurophysics Group, Department of Neurology, Campus Benjamin Franklin, Charité Universitätsmedizin Berlin, Berlin, Germany; Centre for Cognition and Decision Making, Institute for Cognitive Neuroscience, National Research University Higher School of Economics, Moscow, Russia
| | - A Villringer
- Department of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany; MindBrainBody Institute at the Berlin School of Mind and Brain, Humboldt-Universität zu Berlin, Berlin, Germany; Center for Stroke Research Berlin, Charité - Universitätsmedizin Berlin, Berlin, Germany; Department of Cognitive Neurology, University Hospital Leipzig, Leipzig, Germany
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36
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The association between BOLD-based cerebrovascular reactivity (CVR) and end-tidal CO 2 in healthy subjects. Neuroimage 2019; 207:116365. [PMID: 31734432 PMCID: PMC8080082 DOI: 10.1016/j.neuroimage.2019.116365] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 10/25/2019] [Accepted: 11/13/2019] [Indexed: 01/22/2023] Open
Abstract
Cerebrovascular reactivity (CVR) mapping using CO2-inhalation can provide important insight into vascular health. At present, blood-oxygenation-level-dependent (BOLD) MRI acquisition is the most commonly used CVR method due to its high sensitivity, high spatial resolution, and relatively straightforward processing. However, large variations in CVR across subjects and across different sessions of the same subject are often observed, which can cloud the ability of this promising measure in detecting diseases or monitoring treatment responses. The present work aims to identify the physiological components underlying the observed variability in CVR data. When studying the association between CVR value and the subject’s CO2 levels in a total of N = 253 healthy participants, we found that CVR was lower in individuals with a higher basal end-tidal CO2, EtCO2 (slope = −0.0036 ± 0.0008%/mmHg2, p < 0.001), or with a greater EtCO2 change (ΔEtCO2) with hypercapnic condition (slope = −0.0072 ± 0.0018%/mmHg2, p < 0.001). In a within-subject setting, when studying the CVR difference between two repeated scans (with repositioning) in relation to the corresponding differences in basal EtCO2 and ΔEtCO2 (n = 11), it was found that CVR values were lower if the basal EtCO2 or ΔEtCO2 during that particular scan session was greater. The present work suggests that basal physiological state and the level of hypercapnic stimulus intensity should be considered in application studies of CVR in order to reduce inter-subject and intra-subject variations in the data. Potential approaches to use these findings to reduce noise and augment sensitivity are proposed.
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37
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Zheng L, Gao Z, Xiao X, Ye Z, Chen C, Xue G. Reduced Fidelity of Neural Representation Underlies Episodic Memory Decline in Normal Aging. Cereb Cortex 2019; 28:2283-2296. [PMID: 28591851 DOI: 10.1093/cercor/bhx130] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 05/09/2017] [Indexed: 11/14/2022] Open
Abstract
Emerging studies have emphasized the importance of the fidelity of cortical representation in forming enduring episodic memory. No study, however, has examined whether there are age-related reductions in representation fidelity that can explain memory declines in normal aging. Using functional MRI and multivariate pattern analysis, we found that older adults showed reduced representation fidelity in the visual cortex, which accounted for their decreased memory performance even after controlling for the contribution of reduced activation level. This reduced fidelity was specifically due to older adults' poorer item-specific representation, not due to their lower activation level and variance, greater variability in neuro-vascular coupling, or decreased selectivity of categorical representation (i.e., dedifferentiation). Older adults also showed an enhanced subsequent memory effect in the prefrontal cortex based on activation level, and their prefrontal activation was associated with greater fidelity of representation in the visual cortex and better memory performance. The fidelity of cortical representation thus may serve as a promising neural index for better mechanistic understanding of the memory declines and its compensation in normal aging.
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Affiliation(s)
- Li Zheng
- State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, P.R. China
| | - Zhiyao Gao
- Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing, P.R. China.,Department of Psychology, University of Chinese Academy of Sciences, Beijing, P.R. China
| | - Xiaoqian Xiao
- State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, P.R. China
| | - Zhifang Ye
- State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, P.R. China
| | - Chuansheng Chen
- Department of Psychology and Social Behavior, University of California, Irvine, CA, USA
| | - Gui Xue
- State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, P.R. China
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38
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Non-BOLD contrast for laminar fMRI in humans: CBF, CBV, and CMRO2. Neuroimage 2019; 197:742-760. [DOI: 10.1016/j.neuroimage.2017.07.041] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Revised: 07/10/2017] [Accepted: 07/19/2017] [Indexed: 12/22/2022] Open
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39
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Koen JD, Rugg MD. Neural Dedifferentiation in the Aging Brain. Trends Cogn Sci 2019; 23:547-559. [PMID: 31174975 PMCID: PMC6635135 DOI: 10.1016/j.tics.2019.04.012] [Citation(s) in RCA: 164] [Impact Index Per Article: 32.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 04/22/2019] [Accepted: 04/24/2019] [Indexed: 11/17/2022]
Abstract
Many cognitive abilities decline with age even in the absence of detectable pathology. Recent evidence indicates that age-related neural dedifferentiation, operationalized in terms of neural selectivity, may contribute to this decline. We review here work exploring the relationship between neural dedifferentiation, cognition, and age. Compelling evidence for age effects on neural selectivity comes from both non-human animal and human research. However, current data suggest that age does not moderate the observed relationships between neural dedifferentiation and cognitive performance. We propose that functionally significant variance in measures of neural dedifferentiation reflects both age-dependent and age-independent factors. We further propose that the effects of age on neural dedifferentiation do not exclusively reflect detrimental consequences of aging.
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Affiliation(s)
- Joshua D Koen
- Department of Psychology, University of Notre Dame, Notre Dame, IN 46556, USA.
| | - Michael D Rugg
- Center for Vital Longevity, School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, TX 75235, USA
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40
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BOLD signal physiology: Models and applications. Neuroimage 2019; 187:116-127. [DOI: 10.1016/j.neuroimage.2018.03.018] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 02/14/2018] [Accepted: 03/08/2018] [Indexed: 12/14/2022] Open
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41
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Wright ME, Wise RG. Can Blood Oxygenation Level Dependent Functional Magnetic Resonance Imaging Be Used Accurately to Compare Older and Younger Populations? A Mini Literature Review. Front Aging Neurosci 2018; 10:371. [PMID: 30483117 PMCID: PMC6243068 DOI: 10.3389/fnagi.2018.00371] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 10/25/2018] [Indexed: 11/17/2022] Open
Abstract
A wealth of research has investigated the aging brain using blood oxygenation level dependent functional MRI [Blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI)]. However, many studies do not consider the aging of the cerebrovascular system, which can influence the BOLD signal independently from neural activity, limiting what can be inferred when comparing age groups. Here, we discuss the ways in which the aging neurovascular system can impact BOLD fMRI, the consequences for age-group comparisons and possible strategies for mitigation. While BOLD fMRI is a valuable tool in this context, this review highlights the importance of consideration of vascular confounds.
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Affiliation(s)
- Melissa E Wright
- Cardiff University Brain Imaging Research Center, School of Psychology, Cardiff University, Cardiff, United Kingdom.,School of Optometry and Vision Sciences, Cardiff University, Cardiff, United Kingdom
| | - Richard G Wise
- Cardiff University Brain Imaging Research Center, School of Psychology, Cardiff University, Cardiff, United Kingdom
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42
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Suzuki M, Kawagoe T, Nishiguchi S, Abe N, Otsuka Y, Nakai R, Asano K, Yamada M, Yoshikawa S, Sekiyama K. Neural Correlates of Working Memory Maintenance in Advanced Aging: Evidence From fMRI. Front Aging Neurosci 2018; 10:358. [PMID: 30459595 PMCID: PMC6232505 DOI: 10.3389/fnagi.2018.00358] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Accepted: 10/19/2018] [Indexed: 11/13/2022] Open
Abstract
Working memory (WM)-related brain activity is known to be modulated by aging; particularly, older adults demonstrate greater activity than young adults. However, it is still unclear whether the activity increase in older adults is also observed in advanced aging. The present functional magnetic resonance imaging (fMRI) study was designed to clarify the neural correlates of WM in advanced aging. Further, we set out to investigate in the case that adults of advanced age do show age-related increase in WM-related activity, what the functional significance of this over-recruitment might be. Two groups of older adults – “young–old” (61–70 years, n = 17) and “old–old” (77–82 years, n = 16) – were scanned while performing a visual WM task (the n-back task: 0-back and 1-back). WM effects (1-back > 0-back) common to both age groups were identified in several regions, including the bilateral dorsolateral prefrontal cortex (DLPFC), the inferior parietal cortex, and the insula. Greater WM effects in the old–old than in the young–old group were identified in the right caudal DLPFC. These results were replicated when we performed a separate analysis between two age groups with the same level of WM performance (the young–old vs. a “high-performing” subset of the old–old group). There were no regions where WM effects were greater in the young–old group than in the old–old group. Importantly, the magnitude of the over-recruitment WM effects positively correlated with WM performance in the old–old group, but not in the young–old group. The present findings suggest that cortical over-recruitment occurs in advanced old age, and that increased activity may serve a compensatory function in mediating WM performance.
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Affiliation(s)
- Maki Suzuki
- Division of Cognitive Psychology, Faculty of Letters, Kumamoto University, Kumamoto, Japan.,Department of Behavioral Neurology and Neuropsychiatry, United Graduate School of Child Development, Osaka University, Suita, Japan
| | - Toshikazu Kawagoe
- Division of Human and Social Sciences, Graduate School of Social and Cultural Sciences, Kumamoto University, Kumamoto, Japan
| | - Shu Nishiguchi
- Department of Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Nobuhito Abe
- Kokoro Research Center, Kyoto University, Kyoto, Japan
| | - Yuki Otsuka
- Kokoro Research Center, Kyoto University, Kyoto, Japan
| | - Ryusuke Nakai
- Kokoro Research Center, Kyoto University, Kyoto, Japan
| | - Kohei Asano
- Kokoro Research Center, Kyoto University, Kyoto, Japan
| | - Minoru Yamada
- Department of Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | | | - Kaoru Sekiyama
- Division of Cognitive Psychology, Faculty of Letters, Kumamoto University, Kumamoto, Japan.,Graduate School of Advanced Integrated Studies in Human Survivability, Kyoto University, Kyoto, Japan
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43
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The Relationship between Age, Neural Differentiation, and Memory Performance. J Neurosci 2018; 39:149-162. [PMID: 30389841 DOI: 10.1523/jneurosci.1498-18.2018] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 10/21/2018] [Accepted: 10/23/2018] [Indexed: 11/21/2022] Open
Abstract
Healthy aging is associated with decreased neural selectivity (dedifferentiation) in category-selective cortical regions. This finding has prompted the suggestion that dedifferentiation contributes to age-related cognitive decline. Consistent with this possibility, dedifferentiation has been reported to negatively correlate with fluid intelligence in older adults. Here, we examined whether dedifferentiation is associated with performance in another cognitive domain-episodic memory-that is also highly vulnerable to aging. Given the proposed role of dedifferentiation in age-related cognitive decline, we predicted there would be a stronger link between dedifferentiation and episodic memory performance in older than in younger adults. Young (18-30 years) and older (64-75 years) male and female humans underwent fMRI scanning while viewing images of objects and scenes before a subsequent recognition memory test. We computed a differentiation index in two regions of interest (ROIs): parahippocampal place area (PPA) and lateral occipital complex (LOC). This index quantified the selectivity of the BOLD response to preferred versus nonpreferred category of an ROI (scenes for PPA, objects for LOC). The differentiation index in the PPA, but not the LOC, was lower in older than in younger adults. Additionally, the PPA differentiation index predicted recognition memory performance for the studied items. This relationship was independent of and not moderated by age. The PPA differentiation index also predicted performance on a latent "fluency" factor derived from a neuropsychological test battery; this relationship was also age invariant. These findings suggest that two independent factors, one associated with age, and the other with cognitive performance, influence neural differentiation.SIGNIFICANCE STATEMENT Aging is associated with neural dedifferentiation-reduced neural selectivity in "category-selective" cortical brain regions-which has been proposed to contribute to cognitive aging. Here, we examined whether neural differentiation is predictive of episodic memory performance, and whether the relationship is moderated by age. A neural differentiation index was estimated for scene-selective (PPA) and object-selective (LOC) cortical regions while participants studied images for a subsequent memory test. Age-related reductions were observed for the PPA, but not for the LOC, differentiation index. Importantly, the PPA differentiation index demonstrated age-invariant correlations with subsequent memory performance and a fluency factor derived from a neuropsychological battery. Together, these findings suggest that neural differentiation is associated with two independent factors: age and cognitive performance.
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44
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Chiacchiaretta P, Cerritelli F, Bubbico G, Perrucci MG, Ferretti A. Reduced Dynamic Coupling Between Spontaneous BOLD-CBF Fluctuations in Older Adults: A Dual-Echo pCASL Study. Front Aging Neurosci 2018; 10:115. [PMID: 29740310 PMCID: PMC5925323 DOI: 10.3389/fnagi.2018.00115] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Accepted: 04/03/2018] [Indexed: 11/13/2022] Open
Abstract
Measurement of the dynamic coupling between spontaneous Blood Oxygenation Level Dependent (BOLD) and cerebral blood flow (CBF) fluctuations has been recently proposed as a method to probe resting-state brain physiology. Here we investigated how the dynamic BOLD-CBF coupling during resting-state is affected by aging. Fifteen young subjects and 17 healthy elderlies were studied using a dual-echo pCASL sequence. We found that the dynamic BOLD-CBF coupling was markedly reduced in elderlies, in particular in the left supramarginal gyrus, an area known to be involved in verbal working memory and episodic memory. Moreover, correcting for temporal shift between BOLD and CBF timecourses resulted in an increased correlation of the two signals for both groups, but with a larger increase for elderlies. However, even after temporal shift correction, a significantly decreased correlation was still observed for elderlies in the left supramarginal gyrus, indicating that the age-related dynamic BOLD-CBF uncoupling in this region is more pronounced and can be only partially explained with a simple time-shift between the two signals. Interestingly, these results were observed in a group of elderlies with normal cognitive functions, suggesting that the study of dynamic BOLD-CBF coupling during resting-state is a promising technique, potentially able to provide early biomarkers of functional changes in the aging brain.
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Affiliation(s)
- Piero Chiacchiaretta
- Department of Neuroscience, Imaging and Clinical Sciences, Università degli Studi G. d'Annunzio Chieti e Pescara, Chieti, Italy.,Institute for Advanced Biomedical Technologies (ITAB), Università degli Studi G. d'Annunzio Chieti e Pescara, Chieti, Italy
| | - Francesco Cerritelli
- Department of Neuroscience, Imaging and Clinical Sciences, Università degli Studi G. d'Annunzio Chieti e Pescara, Chieti, Italy.,Institute for Advanced Biomedical Technologies (ITAB), Università degli Studi G. d'Annunzio Chieti e Pescara, Chieti, Italy.,Clinical-Based Human Research Department-C.O.M.E. Collaboration ONLUS, Pescara, Italy
| | - Giovanna Bubbico
- Department of Neuroscience, Imaging and Clinical Sciences, Università degli Studi G. d'Annunzio Chieti e Pescara, Chieti, Italy.,Institute for Advanced Biomedical Technologies (ITAB), Università degli Studi G. d'Annunzio Chieti e Pescara, Chieti, Italy
| | - Mauro Gianni Perrucci
- Department of Neuroscience, Imaging and Clinical Sciences, Università degli Studi G. d'Annunzio Chieti e Pescara, Chieti, Italy.,Institute for Advanced Biomedical Technologies (ITAB), Università degli Studi G. d'Annunzio Chieti e Pescara, Chieti, Italy
| | - Antonio Ferretti
- Department of Neuroscience, Imaging and Clinical Sciences, Università degli Studi G. d'Annunzio Chieti e Pescara, Chieti, Italy.,Institute for Advanced Biomedical Technologies (ITAB), Università degli Studi G. d'Annunzio Chieti e Pescara, Chieti, Italy
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45
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Grady CL, Garrett DD. Brain signal variability is modulated as a function of internal and external demand in younger and older adults. Neuroimage 2018; 169:510-523. [DOI: 10.1016/j.neuroimage.2017.12.031] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 11/09/2017] [Accepted: 12/11/2017] [Indexed: 10/18/2022] Open
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46
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Liu P, De Vis JB, Lu H. Cerebrovascular reactivity (CVR) MRI with CO2 challenge: A technical review. Neuroimage 2018; 187:104-115. [PMID: 29574034 DOI: 10.1016/j.neuroimage.2018.03.047] [Citation(s) in RCA: 136] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 02/06/2018] [Accepted: 03/19/2018] [Indexed: 11/16/2022] Open
Abstract
Cerebrovascular reactivity (CVR) is an indicator of cerebrovascular reserve and provides important information about vascular health in a range of brain conditions and diseases. Unlike steady-state vascular parameters, such as cerebral blood flow (CBF) and cerebral blood volume (CBV), CVR measures the ability of cerebral vessels to dilate or constrict in response to challenges or maneuvers. Therefore, CVR mapping requires a physiological challenge while monitoring the corresponding hemodynamic changes in the brain. The present review primarily focuses on methods that use CO2 inhalation as a physiological challenge while monitoring changes in hemodynamic MRI signals. CO2 inhalation has been increasingly used in CVR mapping in recent literature due to its potency in causing vasodilation, rapid onset and cessation of the effect, as well as advances in MRI-compatible gas delivery apparatus. In this review, we first discuss the physiological basis of CVR mapping using CO2 inhalation. We then review the methodological aspects of CVR mapping, including gas delivery apparatus, the timing paradigm of the breathing challenge, the MRI imaging sequence, and data analysis. In addition, we review alternative approaches for CVR mapping that do not require CO2 inhalation.
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Affiliation(s)
- Peiying Liu
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, United States.
| | - Jill B De Vis
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, United States
| | - Hanzhang Lu
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, United States; Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, 21287, United States; F.M. Kirby Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, 21205, United States
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47
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Yan CG, Yang Z, Colcombe SJ, Zuo XN, Milham MP. Concordance among indices of intrinsic brain function: Insights from inter-individual variation and temporal dynamics. Sci Bull (Beijing) 2017; 62:1572-1584. [PMID: 36659475 DOI: 10.1016/j.scib.2017.09.015] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 08/22/2017] [Accepted: 09/15/2017] [Indexed: 01/21/2023]
Abstract
Various resting-state fMRI (R-fMRI) measures have been developed to characterize intrinsic brain activity. While each of these measures has gained a growing presence in the literature, questions remain regarding the common and unique aspects these indices capture. The present work provided a comprehensive examination of inter-individual variation and intra-individual temporal variation for commonly used measures, including fractional amplitude of low frequency fluctuations, regional homogeneity, voxel-mirrored homotopic connectivity, network centrality and global signal correlation. Regardless of whether examining intra-individual or inter-individual variation, we found that these definitionally distinct R-fMRI indices tend to exhibit a relatively high degree of covariation, which doesn't exist in phase randomized surrogate data. As a measure of intrinsic brain function, concordance for R-fMRI indices was negatively correlated with age across individuals (i.e., concordance among functional indices decreased with age). To understand the functional significance of concordance, we noted that higher concordance was generally associated with higher strengths of R-fMRI indices, regardless of whether looking through the lens of inter-individual (i.e., high vs. low concordance participants) or intra-individual (i.e., high vs. low concordance states identified via temporal dynamic analyses) differences. We also noted a linear increase in functional concordance together with the R-fMRI indices through the scan, which may suggest a decrease in arousal. The current study demonstrated an enriched picture regarding the relationship among the R-fMRI indices, as well as provided new insights in examining dynamic states within and between individuals.
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Affiliation(s)
- Chao-Gan Yan
- CAS Key Laboratory of Behavioral Science, Institute of Psychology, Beijing 100101, China; Department of Psychology, University of Chinese Academy of Sciences, Beijing 100101, China; Magnetic Resonance Imaging Research Center, Institute of Psychology, Chinese Academy of Sciences, Beijing 100101, China; Center for Lifespan Innovation of Mind and Brain, Institute of Psychology, Chinese Academy of Sciences, Beijing, China; Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA; Department of Child and Adolescent Psychiatry, NYU Langone Medical Center School of Medicine, New York, NY 10016, USA.
| | - Zhen Yang
- Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA; Center for Neuromodulation in Depression and Stress, Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Child Mind Institute, New York, NY 10022, USA
| | - Stanley J Colcombe
- Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA
| | - Xi-Nian Zuo
- CAS Key Laboratory of Behavioral Science, Institute of Psychology, Beijing 100101, China; Department of Psychology, University of Chinese Academy of Sciences, Beijing 100101, China; Magnetic Resonance Imaging Research Center, Institute of Psychology, Chinese Academy of Sciences, Beijing 100101, China; Center for Lifespan Innovation of Mind and Brain, Institute of Psychology, Chinese Academy of Sciences, Beijing, China
| | - Michael P Milham
- Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA; Child Mind Institute, New York, NY 10022, USA
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48
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Militana AR, Donahue MJ, Sills AK, Solomon GS, Gregory AJ, Strother MK, Morgan VL. Alterations in default-mode network connectivity may be influenced by cerebrovascular changes within 1 week of sports related concussion in college varsity athletes: a pilot study. Brain Imaging Behav 2017; 10:559-68. [PMID: 25972119 DOI: 10.1007/s11682-015-9407-3] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The goal of this pilot study is to use complementary MRI strategies to quantify and relate cerebrovascular reactivity, resting cerebral blood flow and functional connectivity alterations in the first week following sports concussion in college varsity athletes. Seven college athletes (3F/4M, age = 19.7 ± 1.2 years) were imaged 3-6 days following a diagnosed sports related concussion and compared to eleven healthy controls with no history of concussion (5M/6F, 18-23 years, 7 athletes). Cerebrovascular reactivity and functional connectivity were measured using functional MRI during a hypercapnia challenge and via resting-state regional partial correlations, respectively. Resting cerebral blood flow was quantified using arterial spin labeling MRI methods. Group comparisons were made within and between 18 regions of interest. Cerebrovascular reactivity was increased after concussion when averaged across all regions of interest (p = 0.04), and within some default-mode network regions, the anterior cingulate and the right thalamus (p < 0.05) independently. The FC was increased in the concussed athletes within the default-mode network including the left and right hippocampus, precuneus and ventromedial prefrontal cortex (p < 0.01), with measures being linearly related to cerebrovascular reactivity in the hippocampus in the concussed athletes. Significant resting cerebral blood flow changes were not detected between the two groups. This study provides evidence for increased cerebrovascular reactivity and functional connectivity in the medial regions of the default-mode network within days of a single sports related concussion in college athletes. Our findings emphasize the utility of complementary cerebrovascular measures in the interpretation of alterations in functional connectivity following concussion.
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Affiliation(s)
- Adam R Militana
- Department of Radiology and Radiological Sciences, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Manus J Donahue
- Department of Radiology and Radiological Sciences, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Allen K Sills
- Department of Neurosurgery, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Gary S Solomon
- Department of Neurosurgery, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Andrew J Gregory
- Department of Orthopedics, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Megan K Strother
- Department of Radiology and Radiological Sciences, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Victoria L Morgan
- Department of Radiology and Radiological Sciences, Vanderbilt University School of Medicine, Nashville, TN, USA. .,Department of Radiology, Vanderbilt University, 1161 21st Ave South, AA1105 MCN, Nashville, TN, 37232, USA.
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49
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Garrett DD, Lindenberger U, Hoge RD, Gauthier CJ. Age differences in brain signal variability are robust to multiple vascular controls. Sci Rep 2017; 7:10149. [PMID: 28860455 PMCID: PMC5579254 DOI: 10.1038/s41598-017-09752-7] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 07/31/2017] [Indexed: 11/09/2022] Open
Abstract
A host of studies support that younger, better performing adults express greater moment-to-moment blood oxygen level-dependent (BOLD) signal variability (SDBOLD) in various cortical regions, supporting an emerging view that the aging brain may undergo a generalized reduction in dynamic range. However, the exact physiological nature of age differences in SDBOLD remains understudied. In a sample of 29 younger and 45 older adults, we examined the contribution of vascular factors to age group differences in fixation-based SDBOLD using (1) a dual-echo BOLD/pseudo-continuous arterial spin labeling (pCASL) sequence, and (2) hypercapnia via a computer-controlled gas delivery system. We tested the hypothesis that, although SDBOLD may relate to individual differences in absolute cerebral blood flow (CBF), BOLD cerebrovascular reactivity (CVR), or maximum BOLD signal change (M), robust age differences in SDBOLD would remain after multiple statistical controls for these vascular factors. As expected, our results demonstrated that brain regions in which younger adults expressed higher SDBOLD persisted after comprehensive control of vascular effects. Our findings thus further establish BOLD signal variability as an important marker of the aging brain.
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Affiliation(s)
- Douglas D Garrett
- Max Planck UCL Centre for Computational Psychiatry and Ageing Research, Berlin/London, Germany. .,Center for Lifespan Psychology, Max Planck Institute for Human Development, Berlin, Germany.
| | - Ulman Lindenberger
- Max Planck UCL Centre for Computational Psychiatry and Ageing Research, Berlin/London, Germany.,Center for Lifespan Psychology, Max Planck Institute for Human Development, Berlin, Germany.,European University Institute, San Domenico di Fiesole (FI), Fiesole, Italy
| | - Richard D Hoge
- Department of Neurology and Neurosurgery, McGill University, Montreal, Canada
| | - Claudine J Gauthier
- Department of Physics, Concordia University, Montreal, Canada.,PERFORM Centre, Concordia University, Montreal, Canada
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50
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Nair VA, Raut RV, Prabhakaran V. Investigating the Blood Oxygenation Level-Dependent Functional MRI Response to a Verbal Fluency Task in Early Stroke before and after Hemodynamic Scaling. Front Neurol 2017; 8:283. [PMID: 28674515 PMCID: PMC5474460 DOI: 10.3389/fneur.2017.00283] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Accepted: 06/01/2017] [Indexed: 11/30/2022] Open
Abstract
Background and objective Blood oxygenation level-dependent (BOLD) functional MRI (fMRI) has been extensively used as a marker of brain dysfunction and subsequent recovery following stroke. However, growing evidence suggests that straightforward interpretation of BOLD fMRI changes with aging and disease is challenging. In this study, we investigated the effect of calibrating task fMRI data by applying a hemodynamic calibration method using the resting-state fluctuation amplitude (RSFA). Task fMRI responses were obtained during a covert verbal fluency task in a group of early stage stroke patients and matched healthy normal controls. Methods Fifteen acute left hemisphere stroke patients (less than 7 days from stroke; aged 44–84 years, average ~64 years) and 21 healthy controls (aged 55–77 years, average ~61 years) were prospectively studied. All subjects completed a 3-min covert verbal fluency task, and a 10-min eyes-closed resting-state fMRI scan, from which the calibration factor (RSFA) was computed. A behavioral measure on the verbal fluency task was also collected outside the scanner. Whole brain activation volumes and region-of-interest (ROI)-wise percent signal change and activation volumes before and after calibration were computed. Results Between-group differences in whole brain activation volumes, although statistically significant before calibration failed to be significant after calibration. There were significant within-group differences before and after calibration with RSFA. Statistically significant between-group differences on ROI-wise measures before calibration also significantly reduced after calibration. Exploratory brain-behavior correlations revealed a similar pattern: significant correlations before calibration failed to survive after calibration. Discussion and conclusion BOLD fMRI changes with aging and disease is confounded by changes in neurofunctional coupling leading to challenges in the straightforward interpretation of task fMRI results. Application of the hemodynamic calibration using the RSFA technique in the current study appeared to mitigate any differences between stroke and age-matched healthy controls. Our study indicates that estimating neural activity after applying hemodynamic scaling is important for studies of aging and for studies tracking post-stroke changes. We recommend that further investigation of hemodynamic calibration with RSFA in healthy subjects and in stroke in larger samples is necessary.
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Affiliation(s)
- Veena A Nair
- Department of Radiology, University of Wisconsin-Madison, Madison, WI, United States
| | - Ryan V Raut
- Department of Radiology, University of Wisconsin-Madison, Madison, WI, United States
| | - Vivek Prabhakaran
- Department of Radiology, University of Wisconsin-Madison, Madison, WI, United States.,Neuroscience Training Program, University of Wisconsin-Madison, Madison, WI, United States.,Medical Scientist Training Program, University of Wisconsin-Madison, Madison, WI, United States
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