1
|
Shirzad M, Van Riesen J, Behboodpour N, Heath M. 10-min exposure to a 2.5% hypercapnic environment increases cerebral blood blow but does not impact executive function. LIFE SCIENCES IN SPACE RESEARCH 2024; 40:143-150. [PMID: 38245339 DOI: 10.1016/j.lssr.2023.07.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 07/19/2023] [Accepted: 07/20/2023] [Indexed: 01/22/2024]
Abstract
Space travel and exploration are associated with increased ambient CO2 (i.e., a hypercapnic environment). Some work reported that the physiological changes (e.g., increased cerebral blood flow [CBF]) associated with a chronic hypercapnic environment contributes to a "space fog" that adversely impacts cognition and psychomotor performance, whereas other work reported no change or a positive change. Here, we employed the antisaccade task to evaluate whether transient exposure to a hypercapnic environment influences top-down executive function (EF). Antisaccades require a goal-directed eye movement mirror-symmetrical to a target and are an ideal tool for identifying subtle EF changes. Healthy young adults (aged 19-25 years) performed blocks of antisaccade trials prior to (i.e., pre-intervention), during (i.e., concurrent) and after (i.e., post-intervention) 10-min of breathing factional inspired CO2 (FiCO2) of 2.5% (i.e., hypercapnic condition) and during a normocapnic (i.e., control) condition. In both conditions, CBF, ventilatory and cardiorespiratory responses were measured. Results showed that the hypercapnic condition increased CBF, ventilation and end-tidal CO2 and thus demonstrated an expected physiological adaptation to increased FiCO2. Notably, however, null hypothesis and equivalence tests indicated that concurrent and post-intervention antisaccade reaction times were refractory to the hypercapnic environment; that is, transient exposure to a FiCO2 of 2.5% did not produce a real-time or lingering influence on an oculomotor-based measure of EF. Accordingly, results provide a framework that - in part - establishes the FiCO2 percentage and timeline by which high-level EF can be maintained. Future work will explore CBF and EF dynamics during chronic hypercapnic exposure as more direct proxy for the challenges of space flight and exploration.
Collapse
Affiliation(s)
- Mustafa Shirzad
- School of Kinesiology, Faculty of Health Sciences, University of Western Ontario, 1151 Richmond St, London, ON N6A 3K7, Canada
| | - James Van Riesen
- Canadian Centre for Activity and Aging, University of Western Ontario, 1201 Western Rd, London, ON N6G 1H1, Canada
| | - Nikan Behboodpour
- School of Kinesiology, Faculty of Health Sciences, University of Western Ontario, 1151 Richmond St, London, ON N6A 3K7, Canada
| | - Matthew Heath
- School of Kinesiology, Faculty of Health Sciences, University of Western Ontario, 1151 Richmond St, London, ON N6A 3K7, Canada; Canadian Centre for Activity and Aging, University of Western Ontario, 1201 Western Rd, London, ON N6G 1H1, Canada; Graduate Program in Neuroscience, University of Western Ontario, 1151 Richmond St, London, ON N6A 3K7, Canada.
| |
Collapse
|
2
|
Ide K. Acute hypoxia elicits prefrontal oxygenation asymmetry in young adults. NEUROPHOTONICS 2023; 10:045002. [PMID: 37808565 PMCID: PMC10551723 DOI: 10.1117/1.nph.10.4.045002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Revised: 09/11/2023] [Accepted: 09/15/2023] [Indexed: 10/10/2023]
Abstract
Significance Cerebrovascular reactivity can be evaluated by prefrontal cortex (PFC) hemodynamic responses and oxygenation changes secondary to hypoxia using near-infrared spectroscopy (NIRS). However, whether there are hemispheric differences in these NIRS-determined PFC hemodynamic responses and oxygenation changes remains unknown. Aim This study was performed to determine whether there are differences in the PFC hemodynamic responses and oxygenation changes secondary to hypoxia between the left and right frontal poles (FPL and FPR, respectively). Approach Fifteen young men participated in the study. During conduction of an isocapnic hypoxia protocol with a 10-min hypoxic phase at partial pressure of end-tidal oxygen (PET O 2 ) of 45 Torr, hemodynamic and oxygenation indices comprising oxygenated hemoglobin (oxy-Hb), deoxygenated Hb (deoxy-Hb), total Hb (total-Hb), and tissue oxygen saturation (StO 2 ) over FPL and FPR were measured by NIRS. The heart rate (HR) was evaluated by electrocardiography. Results In response to hypoxia, the HR increased, oxy-Hb decreased, deoxy-Hb increased, total-Hb increased above baseline, and StO 2 decreased. There was no difference in the change in total-Hb between FPL and FPR. However, there were greater changes in oxy-Hb, deoxy-Hb, and StO 2 over FPL than over FPR, indicating that PFC oxygenation asymmetry occurs in response to hypoxia. Moreover, the change in total-Hb over FPL was associated with the increase in HR. Conclusions NIRS-determined hemodynamic responses and oxygenation changes secondary to hypoxia might not simply reflect the direct effect of hypoxia on cerebral vessels. Although there is no hemispheric difference in the PFC hemodynamic responses to hypoxia as in total-Hb, PFC oxygenation asymmetry occurs in young adults.
Collapse
Affiliation(s)
- Kojiro Ide
- Hokusho University, School of Lifelong Sport, Northern Region Lifelong Sports Research Center, Hokkaido, Japan
| |
Collapse
|
3
|
Brisson RT, Fernandes RDCL, Arruda JFDL, Rocha TCCDSM, Santos NDGD, Silva LD, de Lima MASD, de Rosso ALZ. Altered Cerebral Vasoreactivity on Transcranial Color-Coded Sonography Related to Akinetic-Rigid Phenotype of Parkinson's Disease: Interim Analysis of a Cross-Sectional Study. Brain Sci 2023; 13:brainsci13050709. [PMID: 37239181 DOI: 10.3390/brainsci13050709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2023] [Revised: 04/13/2023] [Accepted: 04/19/2023] [Indexed: 05/28/2023] Open
Abstract
BACKGROUND A correlation between worse functional outcomes in Parkinson's disease (PD) patients with cerebrovascular disease (CVD) or the Akinetic-rigid phenotype has been argued in recent studies. We aimed to evaluate the association of cerebral hemodynamics impairments, assessed by Transcranial Color-coded Doppler sonography (TCCS), on PD patients with different phenotypes of the disease and with risk factors for CVD. METHODOLOGY Idiopathic PD patients (n = 51) were divided into motor subtypes: Akinetic-rigid (AR) (n = 27) and Tremor-dominant (TD) (n = 24) and into two groups regarding vascular risk factors: when ≥2 were present (PDvasc) (n = 18) and <2 (PDnvasc) (n = 33). In a parallel analysis, the Fazekas scale on brain magnetic resonance imaging (MRI) was applied to a sample to assess the degree of leukoaraiosis. TCCS examinations were prospectively performed obtaining middle cerebral artery Mean Flow Velocities (Vm), Resistance Index (RI), and Pulsatility Index (PI). The Breath-Holding Index (BHI) was calculated to assess cerebrovascular reactivity (cVR). Standardized functional scales were administered (UPDRS III and Hoehn&Yahr). RESULTS The phenotype groups were similar in age, disease duration and demographic parameters, but there were significantly higher H&Y scores than TD group. cVR was impaired in 66.7% of AR vs. 37.5% of TD. AR group exhibited lower BHI (0.53 ± 0.31 vs. 0.91 ± 0.62; p = 0.000), lower Vm after apnea (44.3 ± 9.0 cm/s vs. 53.4 ± 11.4 cm/s; p = 0.003), higher PI (0.91 ± 0.26 vs. 0.76 ± 0.12; p = 0.000) and RI (0.58 ± 0.11 vs. 0.52 ± 0.06; p = 0.021). PDvasc group showed higher PI (0.98 vs. 0.76; p = 0.001) and higher frequency of altered cVR (72.2% vs. 42.2%; p = 0.004). There was a significant predominance of higher values on Fazekas scale in the PDvasc group. We found no difference between the Fazekas scale when comparing motor subtypes groups but there was a trend toward higher scores in the AR phenotype. CONCLUSIONS TCCS, a cost-effective method, displayed impaired cVR in Parkinsonian patients with risk factors for CVD with higher degree of MRI leukoaraiosis. PD patients with the AR disease phenotype also presented impaired cVR on TCCS and greater functional impairment, although with just a trend to higher scores on MRI Fazekas.
Collapse
Affiliation(s)
- Rodrigo Tavares Brisson
- Department of Neurology, Hospital Universitário Clementino Fraga Filho, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro 21941-617, Brazil
| | - Rita de Cássia Leite Fernandes
- Department of Neurology, Hospital Universitário Clementino Fraga Filho, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro 21941-617, Brazil
| | - Josevânia Fulgêncio de Lima Arruda
- Department of Neurology, Hospital Universitário Clementino Fraga Filho, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro 21941-617, Brazil
| | | | - Nathália de Góes Duarte Santos
- Department of Neurology, Hospital Universitário Clementino Fraga Filho, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro 21941-617, Brazil
| | - Liene Duarte Silva
- Department of Neurology, Hospital Universitário Clementino Fraga Filho, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro 21941-617, Brazil
| | - Marco Antônio Sales Dantas de Lima
- Department of Neurology, Hospital Universitário Clementino Fraga Filho, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro 21941-617, Brazil
| | - Ana Lucia Zuma de Rosso
- Department of Neurology, Hospital Universitário Clementino Fraga Filho, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro 21941-617, Brazil
| |
Collapse
|
4
|
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.
Collapse
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)
| |
Collapse
|
5
|
Leacy JK, Johnson EM, Lavoie LR, Macilwraith DN, Bambury M, Martin JA, Lucking EF, Linares AM, Saran G, Sheehan DP, Sharma N, Day TA, O'Halloran KD. Variation within the visually evoked neurovascular coupling response of the posterior cerebral artery is not influenced by age or sex. J Appl Physiol (1985) 2022; 133:335-348. [PMID: 35771218 PMCID: PMC9359642 DOI: 10.1152/japplphysiol.00292.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Neurovascular coupling (NVC) is the temporal and spatial coordination between local neuronal activity and regional cerebral blood flow. The literature is unsettled on whether age and/or sex affect NVC, which may relate to differences in methodology and the quantification of NVC in small sample-sized studies. The aim of this study was to 1) determine the relative and combined contribution of age and sex to the variation observed across several distinct NVC metrics (n = 125, 21–66 yr; 41 males) and 2) present an approach for the comprehensive systematic assessment of the NVC response using transcranial Doppler ultrasound. NVC was measured as the relative change from baseline (absolute and percent change) assessing peak, mean, and total area under the curve (tAUC) of cerebral blood velocity through the posterior cerebral artery (PCAv) during intermittent photic stimulation. In addition, the NVC waveform was compartmentalized into distinct regions, acute (0–9 s), mid (10–19 s), and late (20–30 s), following the onset of photic stimulation. Hierarchical multiple regression modeling was used to determine the extent of variation within each NVC metric attributable to demographic differences in age and sex. After controlling for differences in baseline PCAv, the R2 data suggest that 1.6%, 6.1%, 1.1%, 3.4%, 2.5%, and 4.2% of the variance observed within mean, peak, tAUC, acute, mid, and late response magnitude is attributable to the combination of age and sex. Our study reveals that variability in NVC response magnitude is independent of age and sex in healthy human participants, aged 21–66 yr. NEW & NOTEWORTHY We assessed the variability within the neurovascular coupling response attributable to age and sex (n = 125, 21–66 yr; 41 male). Based on the assessment of posterior cerebral artery responses to visual stimulation, 0%–6% of the variance observed within several metrics of NVC response magnitude are attributable to the combination of age and sex. Therefore, observed differences between age groups and/or sexes are likely a result of other physiological factors.
Collapse
Affiliation(s)
- Jack K Leacy
- Department of Physiology, School of Medicine, College of Medicine and Health, University College Cork, Cork, Ireland
| | - Emily M Johnson
- Department of Biology, Faculty of Science and Technology, Mount Royal University, Calgary, Alberta, Canada
| | - Lauren R Lavoie
- Department of Biology, Faculty of Science and Technology, Mount Royal University, Calgary, Alberta, Canada
| | - Diane N Macilwraith
- Department of Physiology, School of Medicine, College of Medicine and Health, University College Cork, Cork, Ireland
| | - Megan Bambury
- Department of Physiology, School of Medicine, College of Medicine and Health, University College Cork, Cork, Ireland
| | - Jason A Martin
- Department of Physiology, School of Medicine, College of Medicine and Health, University College Cork, Cork, Ireland.,APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - Eric F Lucking
- Department of Physiology, School of Medicine, College of Medicine and Health, University College Cork, Cork, Ireland
| | - Andrea M Linares
- Department of Biology, Faculty of Science and Technology, Mount Royal University, Calgary, Alberta, Canada
| | - Gurkarn Saran
- Department of Biology, Faculty of Science and Technology, Mount Royal University, Calgary, Alberta, Canada
| | - Dwayne P Sheehan
- Department of Biology, Faculty of Science and Technology, Mount Royal University, Calgary, Alberta, Canada
| | - Nishan Sharma
- Department of Community Health Sciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Trevor A Day
- Department of Physiology, School of Medicine, College of Medicine and Health, University College Cork, Cork, Ireland.,Department of Biology, Faculty of Science and Technology, Mount Royal University, Calgary, Alberta, Canada
| | - Ken D O'Halloran
- Department of Physiology, School of Medicine, College of Medicine and Health, University College Cork, Cork, Ireland
| |
Collapse
|
6
|
Martins D, Brodmann K, Veronese M, Dipasquale O, Mazibuko N, Schuschnig U, Zelaya F, Fotopoulou A, Paloyelis Y. "Less is more": a dose-response account of intranasal oxytocin pharmacodynamics in the human brain. Prog Neurobiol 2022; 211:102239. [PMID: 35122880 DOI: 10.1016/j.pneurobio.2022.102239] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 01/23/2022] [Accepted: 01/31/2022] [Indexed: 12/27/2022]
Abstract
Intranasal oxytocin is attracting attention as a potential treatment for several brain disorders due to promising preclinical results. However, translating findings to humans has been hampered by remaining uncertainties about its pharmacodynamics and the methods used to probe its effects in the human brain. Using a dose-response design (9, 18 and 36 IU), we demonstrate that intranasal oxytocin-induced changes in local regional cerebral blood flow (rCBF) in the amygdala at rest, and in the covariance between rCBF in the amygdala and other key hubs of the brain oxytocin system, follow a dose-response curve with maximal effects for lower doses. Yet, the effects on local rCBF might vary by amygdala subdivision, highlighting the need to qualify dose-response curves within subregion. We further link physiological changes with the density of the oxytocin receptor gene mRNA across brain regions, strengthening our confidence in intranasal oxytocin as a valid approach to engage central targets. Finally, we demonstrate that intranasal oxytocin does not disrupt cerebrovascular reactivity, which corroborates the validity of haemodynamic neuroimaging to probe the effects of intranasal oxytocin in the human brain. DATA AVAILABILITY: Participants did not consent for open sharing of the data. Therefore, data can only be accessed from the corresponding author upon reasonable request.
Collapse
Affiliation(s)
- Daniel Martins
- Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's College London, De Crespigny Park, London SE5 8AF, UK
| | - Katja Brodmann
- Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's College London, De Crespigny Park, London SE5 8AF, UK
| | - Mattia Veronese
- Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's College London, De Crespigny Park, London SE5 8AF, UK
| | - Ottavia Dipasquale
- Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's College London, De Crespigny Park, London SE5 8AF, UK
| | - Ndaba Mazibuko
- Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's College London, De Crespigny Park, London SE5 8AF, UK
| | | | - Fernando Zelaya
- Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's College London, De Crespigny Park, London SE5 8AF, UK
| | - Aikaterini Fotopoulou
- Department of Clinical, Educational and Health Psychology, University College London, London, UK
| | - Yannis Paloyelis
- Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's College London, De Crespigny Park, London SE5 8AF, UK.
| |
Collapse
|
7
|
Rodriguez-Sabate C, Morales I, Rodriguez M. The Influence of Aging on the Functional Connectivity of the Human Basal Ganglia. Front Aging Neurosci 2022; 13:785666. [PMID: 35095470 PMCID: PMC8789673 DOI: 10.3389/fnagi.2021.785666] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 12/14/2021] [Indexed: 11/24/2022] Open
Abstract
Although basal ganglia (BG) are involved in the motor disorders of aged people, the effect of aging on the functional interaction of BG is not well-known. This work was aimed at studying the influence of aging on the functional connectivity of the motor circuit of BG (BGmC). Thirty healthy volunteers were studied (young-group 26.4 ± 5.7 years old; aged-group 63.1 ± 5.8 years old) with a procedure planned to prevent the spurious functional connectivity induced by the closed-loop arrangement of the BGmC. BG showed different functional interactions during the inter-task intervals and when subjects did not perform any voluntary task. Aging induced marked changes in the functional connectivity of the BGmC during these inter-task intervals. The finger movements changed the functional connectivity of the BG, these modifications were also different in the aged-group. Taken together, these data show a marked effect of aging on the functional connectivity of the BGmC, and these effects may be at the basis of the motor handicaps of aged people during the execution of motor-tasks and when they are not performing any voluntary motor task.
Collapse
Affiliation(s)
- Clara Rodriguez-Sabate
- Center for Networked Biomedical Research in Neurodegenerative Diseases, Madrid, Spain
- Laboratory of Neurobiology and Experimental Neurology, Department of Basic Medical Sciences, Physiology, Faculty of Medicine, University of La Laguna, San Cristóbal de La Laguna, Spain
| | - Ingrid Morales
- Center for Networked Biomedical Research in Neurodegenerative Diseases, Madrid, Spain
- Laboratory of Neurobiology and Experimental Neurology, Department of Basic Medical Sciences, Physiology, Faculty of Medicine, University of La Laguna, San Cristóbal de La Laguna, Spain
| | - Manuel Rodriguez
- Center for Networked Biomedical Research in Neurodegenerative Diseases, Madrid, Spain
- Laboratory of Neurobiology and Experimental Neurology, Department of Basic Medical Sciences, Physiology, Faculty of Medicine, University of La Laguna, San Cristóbal de La Laguna, Spain
- *Correspondence: Manuel Rodriguez
| |
Collapse
|
8
|
Ultrasonographic Changes in Brain Hemodynamics in Patients with Parkinson's Disease and Risk Factors for Cerebrovascular Disease: A Pilot Study. PARKINSONS DISEASE 2021; 2021:1713496. [PMID: 34650786 PMCID: PMC8510819 DOI: 10.1155/2021/1713496] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Revised: 09/20/2021] [Accepted: 09/24/2021] [Indexed: 12/13/2022]
Abstract
Recent epidemiological studies have revealed a correlation between atypical features and worse functional outcomes in Parkinson's disease (PD) patients with cerebrovascular disease (CVD). We aimed to evaluate the brain hemodynamics of PD patients with risk factors for CVD using Doppler ultrasonography. In this prospective pilot study, we randomly included 27 outpatients diagnosed with PD. Transcranial color-coded sonography (TCCS) examinations were performed, obtaining measurements of middle cerebral artery mean flow velocities (Vm), the resistance index (RI), and the pulsatility index (PI). The breath-holding index (BHI) was used to assess cerebrovascular reactivity (cVR). Standardized functional scales (UPDRS III, Hoehn & Yahr scale, and MoCA) were administered. The patients were divided into two groups: those with two or more vascular risk factors (PDvasc) and those with fewer than two vascular risk factors (PDnvasc). Patients in the PDvasc group showed higher PI (1.00 vs. 0.85; p=0.020), RI (0.59 vs. 0.5; p=0.05), H&Y mean (2.4 vs. 1.4; p=0.036), higher frequency of altered cVR (90.9% vs. 25.0%; p=0.001), and lower BHI (0.46 vs. 1.01; p=0.027). We also divided the patients in other two groups: one with patients with classical and another with akinetic-rigid PD clinical type. Patients with the akinetic-rigid type of PD had significantly higher RI (0.60 vs. 0.51; p=0.03), PI (0.99 vs. 0.77; p=0.03), higher frequency of altered cVR (80% vs. 35%; p=0.02), and lower BHI (0.48 vs. 0.96; p=0.05) than patients with classic-type PD. We concluded that TCCS displays impaired cerebrovascular reactivity and a more severe disease pattern in Parkinsonian patients with two or more risk factors for CVD and in the akinetic-rigid type. Doppler ultrasonography may be a useful tool in a clinical setting to investigate PD patients.
Collapse
|
9
|
Yabluchanskiy A, Nyul-Toth A, Csiszar A, Gulej R, Saunders D, Towner R, Turner M, Zhao Y, Abdelkari D, Rypma B, Tarantini S. Age-related alterations in the cerebrovasculature affect neurovascular coupling and BOLD fMRI responses: Insights from animal models of aging. Psychophysiology 2021; 58:e13718. [PMID: 33141436 PMCID: PMC9166153 DOI: 10.1111/psyp.13718] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 08/10/2020] [Accepted: 09/28/2020] [Indexed: 12/11/2022]
Abstract
The present and future research efforts in cognitive neuroscience and psychophysiology rely on the measurement, understanding, and interpretation of blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging (fMRI) to effectively investigate brain function. Aging and age-associated pathophysiological processes change the structural and functional integrity of the cerebrovasculature which can significantly alter how the BOLD signal is recorded and interpreted. In order to gain an improved understanding of the benefits, drawbacks, and methodological implications for BOLD fMRI in the context of cognitive neuroscience, it is crucial to understand the cellular and molecular mechanism of age-related vascular pathologies. This review discusses the multifaceted effects of aging and the contributions of age-related pathologies on structural and functional integrity of the cerebral microcirculation as they has been investigated in animal models of aging, including age-related alterations in neurovascular coupling responses, cellular and molecular mechanisms involved in microvascular damage, vascular rarefaction, blood-brain barrier disruption, senescence, humoral deficiencies as they relate to, and potentially introduce confounding factors in the interpretation of BOLD fMRI.
Collapse
Affiliation(s)
- Andriy Yabluchanskiy
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Adam Nyul-Toth
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA,Institute of Biophysics, Biological Research Centre, Szeged, Hungary
| | - Anna Csiszar
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Rafal Gulej
- Advanced Magnetic Resonance Center, Oklahoma Medical Research Foundation, Oklahoma, OK, USA
| | - Debra Saunders
- Advanced Magnetic Resonance Center, Oklahoma Medical Research Foundation, Oklahoma, OK, USA
| | - Rheal Towner
- Advanced Magnetic Resonance Center, Oklahoma Medical Research Foundation, Oklahoma, OK, USA
| | - Monroe Turner
- School of Behavioral and Brain Sciences, University of Texas at Dallas, Dallas, TX, USA
| | - Yuguang Zhao
- School of Behavioral and Brain Sciences, University of Texas at Dallas, Dallas, TX, USA
| | - Dema Abdelkari
- School of Behavioral and Brain Sciences, University of Texas at Dallas, Dallas, TX, USA
| | - Bart Rypma
- School of Behavioral and Brain Sciences, University of Texas at Dallas, Dallas, TX, USA,Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Stefano Tarantini
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA,International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine/Department of Public Health, Semmelweis University, Budapest, Hungary,Department of Health Promotion Sciences, College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| |
Collapse
|
10
|
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.
Collapse
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
| |
Collapse
|
11
|
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.
Collapse
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
| |
Collapse
|
12
|
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.
Collapse
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
| |
Collapse
|
13
|
Pinto J, Bright MG, Bulte DP, Figueiredo P. Cerebrovascular Reactivity Mapping Without Gas Challenges: A Methodological Guide. Front Physiol 2021; 11:608475. [PMID: 33536935 PMCID: PMC7848198 DOI: 10.3389/fphys.2020.608475] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 12/02/2020] [Indexed: 01/08/2023] Open
Abstract
Cerebrovascular reactivity (CVR) is defined as the ability of vessels to alter their caliber in response to vasoactive factors, by means of dilating or constricting, in order to increase or decrease regional cerebral blood flow (CBF). Importantly, CVR may provide a sensitive biomarker for pathologies where vasculature is compromised. Furthermore, the spatiotemporal dynamics of CVR observed in healthy subjects, reflecting regional differences in cerebral vascular tone and response, may also be important in functional MRI studies based on neurovascular coupling mechanisms. Assessment of CVR is usually based on the use of a vasoactive stimulus combined with a CBF measurement technique. Although transcranial Doppler ultrasound has been frequently used to obtain global flow velocity measurements, MRI techniques are being increasingly employed for obtaining CBF maps. For the vasoactive stimulus, vasodilatory hypercapnia is usually induced through the manipulation of respiratory gases, including the inhalation of increased concentrations of carbon dioxide. However, most of these methods require an additional apparatus and complex setups, which not only may not be well-tolerated by some populations but are also not widely available. For these reasons, strategies based on voluntary breathing fluctuations without the need for external gas challenges have been proposed. These include the task-based methodologies of breath holding and paced deep breathing, as well as a new generation of methods based on spontaneous breathing fluctuations during resting-state. Despite the multitude of alternatives to gas challenges, existing literature lacks definitive conclusions regarding the best practices for the vasoactive modulation and associated analysis protocols. In this work, we perform an extensive review of CVR mapping techniques based on MRI and CO2 variations without gas challenges, focusing on the methodological aspects of the breathing protocols and corresponding data analysis. Finally, we outline a set of practical guidelines based on generally accepted practices and available data, extending previous reports and encouraging the wider application of CVR mapping methodologies in both clinical and academic MRI settings.
Collapse
Affiliation(s)
- Joana Pinto
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford, United Kingdom
- Institute for Systems and Robotics - Lisboa and Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
| | - Molly G. Bright
- Physical Therapy and Human Movement Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
- Biomedical Engineering, McCormick School of Engineering, Northwestern University, Evanston, IL, United States
| | - Daniel P. Bulte
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford, United Kingdom
| | - Patrícia Figueiredo
- Institute for Systems and Robotics - Lisboa and Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
| |
Collapse
|
14
|
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'.
Collapse
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
| |
Collapse
|
15
|
Yang HCS, Liang Z, Vike NL, Lee T, Rispoli JV, Nauman EA, Talavage TM, Tong Y. Characterizing near-infrared spectroscopy signal under hypercapnia. JOURNAL OF BIOPHOTONICS 2020; 13:e202000173. [PMID: 32706517 DOI: 10.1002/jbio.202000173] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 07/11/2020] [Accepted: 07/20/2020] [Indexed: 06/11/2023]
Abstract
Vasoactive stress tests (i.e. hypercapnia, elevated partial pressure of arterial CO2 [PaCO2 ]) are commonly used in functional MRI (fMRI), to induce cerebral blood flow changes and expose hidden perfusion deficits in the brain. Compared with fMRI, near-infrared spectroscopy (NIRS) is an alternative low-cost, real-time, and non-invasive tool, which can be applied in out-of-hospital settings. To develop and optimize vasoactive stress tests for NIRS, several hypercapnia-induced tasks were tested using concurrent-NIRS/fMRI on healthy subjects. The results indicated that the cerebral and extracerebral reactivity to elevated PaCO2 depended on the rate of the CO2 increase. A steep increase resulted in different cerebral and extracerebral reactivities, leading to unpredictable NIRS measurements compared with fMRI. However, a ramped increase, induced by ramped-CO2 inhalation or breath-holding tasks, induced synchronized cerebral, and extracerebral reactivities, resulting in consistent NIRS and fMRI measurements. These results demonstrate that only tasks that increase PaCO2 gradually can produce reliable NIRS results.
Collapse
Affiliation(s)
- Ho-Ching Shawn Yang
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana, USA
| | - Zhenhu Liang
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana, USA
- Institute of Electrical Engineering, Yanshan University, Qinhuangdao, China
| | - Nicole L Vike
- Department of Basic Medical Sciences, Purdue University, West Lafayette, Indiana, USA
| | - Taylor Lee
- School of Mechanical Engineering, Purdue University, West Lafayette, Indiana, USA
| | - Joseph V Rispoli
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana, USA
- School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana, USA
| | - Eric A Nauman
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana, USA
- School of Mechanical Engineering, Purdue University, West Lafayette, Indiana, USA
| | - Thomas M Talavage
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana, USA
- School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana, USA
| | - Yunjie Tong
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana, USA
| |
Collapse
|
16
|
Anderson AE, Diaz-Santos M, Frei S, Dang BH, Kaur P, Lyden P, Buxton R, Douglas PK, Bilder RM, Esfandiari M, Friston KJ, Nookala U, Bookheimer SY. Hemodynamic latency is associated with reduced intelligence across the lifespan: an fMRI DCM study of aging, cerebrovascular integrity, and cognitive ability. Brain Struct Funct 2020; 225:1705-1717. [PMID: 32474754 DOI: 10.1007/s00429-020-02083-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Accepted: 05/04/2020] [Indexed: 10/24/2022]
Abstract
Changes in neurovascular coupling are associated with both Alzheimer's disease and vascular dementia in later life, but this may be confounded by cerebrovascular risk. We hypothesized that hemodynamic latency would be associated with reduced cognitive functioning across the lifespan, holding constant demographic and cerebrovascular risk. In 387 adults aged 18-85 (mean = 48.82), dynamic causal modeling was used to estimate the hemodynamic response function in the left and right V1 and V3-ventral regions of the visual cortex in response to a simple checkerboard block design stimulus with minimal cognitive demands. The hemodynamic latency (transit time) in the visual cortex was used to predict general cognitive ability (Full-Scale IQ), controlling for demographic variables (age, race, education, socioeconomic status) and cerebrovascular risk factors (hypertension, alcohol use, smoking, high cholesterol, BMI, type 2 diabetes, cardiac disorders). Increased hemodynamic latency in the visual cortex predicted reduced cognitive function (p < 0.05), holding constant demographic and cerebrovascular risk. Increased alcohol use was associated with reduced overall cognitive function (Full Scale IQ 2.8 pts, p < 0.05), while cardiac disorders (Full Scale IQ 3.3 IQ pts; p < 0.05), high cholesterol (Full Scale IQ 3.9 pts; p < 0.05), and years of education (2 IQ pts/year; p < 0.001) were associated with higher general cognitive ability. Increased hemodynamic latency was associated with reduced executive functioning (p < 0.05) as well as reductions in verbal concept formation (p < 0.05) and the ability to synthesize and analyze abstract visual information (p < 0.01). Hemodynamic latency is associated with reduced cognitive ability across the lifespan, independently of other demographic and cerebrovascular risk factors. Vascular health may predict cognitive ability long before the onset of dementias.
Collapse
Affiliation(s)
- Ariana E Anderson
- Department of Psychiatry and Biobehavioral Sciences, University of California, 760 Westwood Plaza, Suite 28-224, Los Angeles, 90095, USA. .,Department of Statistics, University of California, Los Angeles, USA.
| | - Mirella Diaz-Santos
- Department of Psychiatry and Biobehavioral Sciences, University of California, 760 Westwood Plaza, Suite 28-224, Los Angeles, 90095, USA
| | - Spencer Frei
- Department of Psychiatry and Biobehavioral Sciences, University of California, 760 Westwood Plaza, Suite 28-224, Los Angeles, 90095, USA.,Department of Statistics, University of California, Los Angeles, USA
| | - Bianca H Dang
- Department of Psychiatry and Biobehavioral Sciences, University of California, 760 Westwood Plaza, Suite 28-224, Los Angeles, 90095, USA
| | - Pashmeen Kaur
- Department of Statistics, University of California, Los Angeles, USA.,Department of Statistics, Ohio State University, Columbus, USA
| | - Patrick Lyden
- Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Richard Buxton
- Department of Radiology, University of California, San Diego, USA
| | - Pamela K Douglas
- Department of Psychiatry and Biobehavioral Sciences, University of California, 760 Westwood Plaza, Suite 28-224, Los Angeles, 90095, USA.,Institute for Simulation and Training, University of Central Florida, Orlando, USA
| | - Robert M Bilder
- Department of Psychiatry and Biobehavioral Sciences, University of California, 760 Westwood Plaza, Suite 28-224, Los Angeles, 90095, USA
| | | | - Karl J Friston
- Institute of Neurology, University College London, London, UK
| | - Usha Nookala
- Department of Psychiatry and Biobehavioral Sciences, University of California, 760 Westwood Plaza, Suite 28-224, Los Angeles, 90095, USA
| | - Susan Y Bookheimer
- Department of Psychiatry and Biobehavioral Sciences, University of California, 760 Westwood Plaza, Suite 28-224, Los Angeles, 90095, USA
| |
Collapse
|
17
|
McIntosh RC, Hoshi RA, Timpano KR. Take my breath away: Neural activation at breath-hold differentiates individuals with panic disorder from healthy controls. Respir Physiol Neurobiol 2020; 277:103427. [PMID: 32120012 DOI: 10.1016/j.resp.2020.103427] [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: 09/14/2019] [Revised: 02/12/2020] [Accepted: 02/24/2020] [Indexed: 01/04/2023]
Abstract
There is neuroanatomical evidence of an "extended fear network" of brain structures involved in the etiology of panic disorder (PD). Although ventilatory distrubance is a primary symptom of PD these sensations may also trigger onset of a panic attack (PA). Here, a voluntary breath-holding paradigm was used to mimic the hypercapnia state in order to compare blood oxygen level-dependent (BOLD) response, at the peak of a series of 18 s breath-holds, of 21 individuals with PD to 21 low anxiety matched controls. Compared to the rest condition, BOLD activity at the peak (12 - 18 s) of the breath-hold was greater for PD versus controls within a number of structures implicated in the extended fear network, including hippocampus, thalamus, and brainstem. Activation was also observed in cortical structures that are shown to be involved in interoceptive and self-referential processing, such as right insula, middle frontal gyrus, and precuneus/posterior cingulate. In lieu of amygdala activation, our findings show elevated activity throughout an extended network of cortical and subcortical structures involved in contextual, interoceptive and self-referential processing when individuals with PD engage in voluntary breath-holding.
Collapse
Affiliation(s)
- R C McIntosh
- Department of Psychology, University of Miami, 1120 NW 14th Street, Miami, FL, 33136, United States.
| | - R A Hoshi
- Clinical and Epidemiological Research Center, Sao Paulo University. 2565 Professor Lineu Prestes Ave, Sao Paulo, 05508-000, Brazil
| | - K R Timpano
- Department of Psychology, University of Miami, 1120 NW 14th Street, Miami, FL, 33136, United States
| |
Collapse
|
18
|
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]
|
19
|
Abstract
Purpose of Review Risks for developing cardiovascular disease and cognitive decline increase with age. In women, these risks may be influenced by pregnancy history. This review provides an integrated evaluation of associations of pregnancy history with hypertension, brain atrophy, and cognitive decline in postmenopausal women. Recent Findings Atrophy in the occipital lobes of the brain was evident in women who had current hypertension and a history of preeclampsia. Deficits in visual memory in women with a history of preeclampsia are consistent with these brain structural changes. The blood velocity response to chemical and sympathoexcitatory stimuli were altered in women with a history of preeclampsia linking impairments in cerebrovascular regulation to the structural and functional changes in the brain. Summary Having a history of preeclampsia should require close monitoring of blood pressure and initiation of anti-hypertensive treatment in perimenopausal women. Mechanisms by which preeclampsia affects cerebrovascular structure and function require additional study.
Collapse
Affiliation(s)
- Kathleen B Miller
- Department of Kinesiology, University of Wisconsin-Madison, Madison, WI, USA
| | - Virginia M Miller
- Department of Surgery, Mayo Clinic, Medical Sci Bldg 421, 200 First St SW, Rochester, MN, 55905, USA.
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Medical Sci Bldg 421, 200 First St SW, Rochester, MN, 55905, USA.
| | - Jill N Barnes
- Department of Kinesiology, University of Wisconsin-Madison, Madison, WI, USA
| |
Collapse
|
20
|
Bálint AR, Puskás T, Menyhárt Á, Kozák G, Szenti I, Kónya Z, Marek T, Bari F, Farkas E. Aging Impairs Cerebrovascular Reactivity at Preserved Resting Cerebral Arteriolar Tone and Vascular Density in the Laboratory Rat. Front Aging Neurosci 2019; 11:301. [PMID: 31780917 PMCID: PMC6856663 DOI: 10.3389/fnagi.2019.00301] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 10/21/2019] [Indexed: 12/26/2022] Open
Abstract
The age-related (mal)adaptive modifications of the cerebral microvascular system have been implicated in cognitive impairment and worse outcomes after ischemic stroke. The magnitude of the hyperemic response to spreading depolarization (SD), a recognized principle of ischemic lesion development has also been found to be reduced by aging. Here, we set out to investigate whether the SD-coupled reactivity of the pial arterioles is subject to aging, and whether concomitant vascular rarefaction may contribute to the age-related insufficiency of the cerebral blood flow (CBF) response. CBF was assessed with laser-speckle contrast analysis (LASCA), and the tone adjustment of pial arterioles was followed with intrinsic optical signal (IOS) imaging at green light illumination through a closed cranial window created over the parietal cortex of isoflurane-anesthetized young (2 months old) and old (18 months old) male Sprague-Dawley rats. Global forebrain ischemia and later reperfusion were induced by the bilateral occlusion and later release of both common carotid arteries. SDs were elicited repeatedly with topical 1M KCl. Pial vascular density was measured in green IOS images of the brain surface, while the density and resting diameter of the cortical penetrating vasculature was estimated with micro-computed tomography of paraformaldehyde-fixed cortical samples. Whilst pial arteriolar dilation in response to SD or ischemia induction were found reduced in the old rat brain, the density and resting diameter of pial cortical vessels, and the degree of SD-related oligemia emerged as variables unaffected by age in our experiments. Spatial flow distribution analysis identified an age-related shift to a greater representation of higher flow ranges in the reperfused cortex. According to our data, impairment of functional arteriolar dilation, at preserved vascular density and resting vascular tone, may be implicated in the age-related deficit of the CBF response to SD, and possibly in the reduced efficacy of neurovascular coupling in the aging brain. SD has been recognized as a potent pathophysiological contributor to ischemic lesion expansion, in part because of the insufficiency of the associated CBF response. Therefore, the age-related impairment of cerebral vasoreactivity as shown here is suggested to contribute to the age-related acceleration of ischemic lesion development.
Collapse
Affiliation(s)
- Armand R. Bálint
- Department of Medical Physics and Informatics, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Tamás Puskás
- Department of Medical Physics and Informatics, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Ákos Menyhárt
- Department of Medical Physics and Informatics, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Gábor Kozák
- Department of Physiology, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Imre Szenti
- Department of Applied and Environmental Chemistry, Interdisciplinary Excellence Centre, University of Szeged, Szeged, Hungary
| | - Zoltán Kónya
- Department of Applied and Environmental Chemistry, Interdisciplinary Excellence Centre, University of Szeged, Szeged, Hungary
- MTA-SZTE Reaction Kinetics and Surface Chemistry Research Group, University of Szeged, Szeged, Hungary
| | - Tamás Marek
- Department of Medical Physics and Informatics, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Ferenc Bari
- Department of Medical Physics and Informatics, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Eszter Farkas
- Department of Medical Physics and Informatics, Faculty of Medicine, University of Szeged, Szeged, Hungary
| |
Collapse
|
21
|
West KL, Zuppichini MD, Turner MP, Sivakolundu DK, Zhao Y, Abdelkarim D, Spence JS, Rypma B. BOLD hemodynamic response function changes significantly with healthy aging. Neuroimage 2018; 188:198-207. [PMID: 30529628 DOI: 10.1016/j.neuroimage.2018.12.012] [Citation(s) in RCA: 89] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 12/04/2018] [Accepted: 12/05/2018] [Indexed: 12/22/2022] Open
Abstract
Functional magnetic resonance imaging (fMRI) has been used to infer age-differences in neural activity from the hemodynamic response function (HRF) that characterizes the blood-oxygen-level-dependent (BOLD) signal over time. BOLD literature in healthy aging lacks consensus in age-related HRF changes, the nature of those changes, and their implications for measurement of age differences in brain function. Between-study discrepancies could be due to small sample sizes, analysis techniques, and/or physiologic mechanisms. We hypothesize that, with large sample sizes and minimal analysis assumptions, age-related changes in HRF parameters could reflect alterations in one or more components of the neural-vascular coupling system. To assess HRF changes in healthy aging, we analyzed the large population-derived dataset from the Cambridge Center for Aging and Neuroscience (CamCAN) study (Shafto et al., 2014). During scanning, 74 younger (18-30 years of age) and 173 older participants (54-74 years of age) viewed two checkerboards to the left and right of a central fixation point, simultaneously heard a binaural tone, and responded via right index finger button-press. To assess differences in the shape of the HRF between younger and older groups, HRFs were estimated using FMRIB's Linear Optimal Basis Sets (FLOBS) to minimize a priori shape assumptions. Group mean HRFs were different between younger and older groups in auditory, visual, and motor cortices. Specifically, we observed increased time-to-peak and decreased peak amplitude in older compared to younger adults in auditory, visual, and motor cortices. Changes in the shape and timing of the HRF in healthy aging, in the absence of performance differences, support our hypothesis of age-related changes in the neural-vascular coupling system beyond neural activity alone. More precise interpretations of HRF age-differences can be formulated once these physiologic factors are disentangled and measured separately.
Collapse
Affiliation(s)
- Kathryn L West
- University of Texas at Dallas, School of Behavioral and Brain Sciences, USA.
| | - Mark D Zuppichini
- University of Texas at Dallas, School of Behavioral and Brain Sciences, USA
| | - Monroe P Turner
- University of Texas at Dallas, School of Behavioral and Brain Sciences, USA
| | | | - Yuguang Zhao
- University of Texas at Dallas, School of Behavioral and Brain Sciences, USA
| | - Dema Abdelkarim
- University of Texas at Dallas, School of Behavioral and Brain Sciences, USA
| | - Jeffrey S Spence
- University of Texas at Dallas, School of Behavioral and Brain Sciences, USA
| | - Bart Rypma
- University of Texas at Dallas, School of Behavioral and Brain Sciences, USA
| |
Collapse
|
22
|
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.
Collapse
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
| |
Collapse
|
23
|
Urback AL, Metcalfe AWS, Korczak DJ, MacIntosh BJ, Goldstein BI. Magnetic resonance imaging of cerebrovascular reactivity in healthy adolescents. J Neurosci Methods 2018; 306:1-9. [PMID: 29879447 DOI: 10.1016/j.jneumeth.2018.06.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 05/24/2018] [Accepted: 06/02/2018] [Indexed: 10/14/2022]
Abstract
BACKGROUND Cerebrovascular reactivity (CVR), an important measure of cerebrovascular health in adults, has not been examined in healthy adolescents. Beyond the direct importance of understanding CVR in healthy youth, studies on this topic can yield insights regarding brain disease. We set out to evaluate 3 different CVR modelling approaches. NEW METHOD Thirty-nine healthy adolescents (ages 13-19 years, 20 females) completed six blocks of 15-second breath-holds separated by 30-second blocks of free-breathing. CVR was measured using blood-oxygenation-level dependent functional magnetic resonance imaging at 3-Tesla; voxel-wise analyses were complemented by regional analyses in five major subdivisions of the brain. Hemodynamic response functions were modelled using: (1) an individualized delay term (double-gamma variate convolved with a boxcar function), (2) with a standard 9-second delay term, and (3) a sine-cosine regressor. RESULTS Individual-delay yielded superior model fit or larger cluster volumes. Regional analysis found differences in CVR and time-to-peak CVR. Males had higher brain-wide CVR in comparison to females (p = 0.025, η2part = 0.345). BMI and blood pressure were not significantly associated with CVR (all p > 0.4). COMPARISON WITH EXISTING METHODS This was the first study to compare these methods in youth. Regional differences were similar to adult studies. CONCLUSIONS These findings lend support to future breath-hold CVR studies in youth, and highlight the merit of applying individualized-delay estimates. Regional variability and sex-related differences in CVR suggest that these variables should be considered in future studies, particularly those that examine disease states with predilection for specific brain regions or those diseases characterized by sex differences.
Collapse
Affiliation(s)
- Adam L Urback
- Department of Psychiatry, Sunnybrook Health Sciences Centre, 2075 Bayview Ave., FG-53, Toronto, ON, M4N 3M5, Canada; Department of Pharmacology, University of Toronto, Medicine, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada.
| | - Arron W S Metcalfe
- Department of Psychiatry, Sunnybrook Health Sciences Centre, 2075 Bayview Ave., FG-53, Toronto, ON, M4N 3M5, Canada; Canadian Partnership for Stroke Recovery, Sunnybrook Health Sciences Centre, 2075 Bayview Ave., Room M6 180, Toronto, ON, M4N 3M5, Canada.
| | - Daphne J Korczak
- Department of Psychiatry, University of Toronto, Medicine, 250 College Street, Room 835, Toronto, ON, M5T 1R8, Canada; Department of Psychiatry, Hospital For Sick Children, 555 University Avenue, Room 1145, Elm Wing, Toronto, ON, M5G 1X8, Canada.
| | - Bradley J MacIntosh
- Canadian Partnership for Stroke Recovery, Sunnybrook Health Sciences Centre, 2075 Bayview Ave., Room M6 180, Toronto, ON, M4N 3M5, Canada; University of Toronto, Department of Medical Biophysics, 101 College Street Suite 15-701, Toronto, ON, M5G 1L7, Canada.
| | - Benjamin I Goldstein
- Department of Psychiatry, Sunnybrook Health Sciences Centre, 2075 Bayview Ave., FG-53, Toronto, ON, M4N 3M5, Canada; Department of Pharmacology, University of Toronto, Medicine, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada; Department of Psychiatry, University of Toronto, Medicine, 250 College Street, Room 835, Toronto, ON, M5T 1R8, Canada.
| |
Collapse
|
24
|
Barnes JN, Harvey RE, Miller KB, Jayachandran M, Malterer KR, Lahr BD, Bailey KR, Joyner MJ, Miller VM. Cerebrovascular Reactivity and Vascular Activation in Postmenopausal Women With Histories of Preeclampsia. Hypertension 2017; 71:110-117. [PMID: 29158356 DOI: 10.1161/hypertensionaha.117.10248] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 10/06/2017] [Accepted: 10/26/2017] [Indexed: 12/21/2022]
Abstract
Cerebrovascular reactivity (CVR) is reduced in patients with cognitive decline. Women with a history of preeclampsia are at increased risk for cognitive decline. This study examined an association between pregnancy history and CVR using a subgroup of 40 age- and parity-matched pairs of women having histories of preeclampsia (n=27) or normotensive pregnancy (n=29) and the association of activated blood elements with CVR. Middle cerebral artery velocity was measured by Doppler ultrasound before and during hypercapnia to assess CVR. Thirty-eight parameters of blood cellular elements, microvesicles, and cell-cell interactions measured in venous blood were assessed for association with CVR using principal component analysis. Middle cerebral artery velocity was lower in the preeclampsia compared with the normotensive group at baseline (63±4 versus 73±3 cm/s; P=0.047) and during hypercapnia (P=0.013-0.056). CVR was significantly lower in the preeclampsia compared with the normotensive group (2.1±1.3 versus 2.9±1.1 cm·s·mm Hg; P=0.009). Globally, the association of the 7 identified principal components with preeclampsia (P=0.107) and with baseline middle cerebral artery velocity (P=0.067) did not reach statistical significance. The interaction between pregnancy history and principal components with respect to CVR (P=0.084) was driven by a nominally significant interaction between preeclampsia and the individual principal component defined by blood elements, platelet aggregation, and interactions of platelets with monocytes and granulocytes (P=0.008). These results suggest that having a history of preeclampsia negatively affects the cerebral circulation years beyond the pregnancy and that this effect was associated with activated blood elements.
Collapse
Affiliation(s)
- Jill N Barnes
- From the Bruno Balke Biodynamics Laboratory, Department of Kinesiology, University of Wisconsin-Madison (J.N.B., K.B.M.); and Department of Anesthesiology (J.N.B., K.R.M., M.J.J.), College of Medicine and Science (R.E.H.), Department of Physiology and Biomedical Engineering (M.J., V.M.M.), Heath Science Research, Division of Epidemiology and Biostatistics (B.D.L., K.R.B.), and Department of Surgery (V.M.M.), Mayo Clinic, Rochester, MN.
| | - Ronée E Harvey
- From the Bruno Balke Biodynamics Laboratory, Department of Kinesiology, University of Wisconsin-Madison (J.N.B., K.B.M.); and Department of Anesthesiology (J.N.B., K.R.M., M.J.J.), College of Medicine and Science (R.E.H.), Department of Physiology and Biomedical Engineering (M.J., V.M.M.), Heath Science Research, Division of Epidemiology and Biostatistics (B.D.L., K.R.B.), and Department of Surgery (V.M.M.), Mayo Clinic, Rochester, MN
| | - Kathleen B Miller
- From the Bruno Balke Biodynamics Laboratory, Department of Kinesiology, University of Wisconsin-Madison (J.N.B., K.B.M.); and Department of Anesthesiology (J.N.B., K.R.M., M.J.J.), College of Medicine and Science (R.E.H.), Department of Physiology and Biomedical Engineering (M.J., V.M.M.), Heath Science Research, Division of Epidemiology and Biostatistics (B.D.L., K.R.B.), and Department of Surgery (V.M.M.), Mayo Clinic, Rochester, MN
| | - Muthuvel Jayachandran
- From the Bruno Balke Biodynamics Laboratory, Department of Kinesiology, University of Wisconsin-Madison (J.N.B., K.B.M.); and Department of Anesthesiology (J.N.B., K.R.M., M.J.J.), College of Medicine and Science (R.E.H.), Department of Physiology and Biomedical Engineering (M.J., V.M.M.), Heath Science Research, Division of Epidemiology and Biostatistics (B.D.L., K.R.B.), and Department of Surgery (V.M.M.), Mayo Clinic, Rochester, MN
| | - Katherine R Malterer
- From the Bruno Balke Biodynamics Laboratory, Department of Kinesiology, University of Wisconsin-Madison (J.N.B., K.B.M.); and Department of Anesthesiology (J.N.B., K.R.M., M.J.J.), College of Medicine and Science (R.E.H.), Department of Physiology and Biomedical Engineering (M.J., V.M.M.), Heath Science Research, Division of Epidemiology and Biostatistics (B.D.L., K.R.B.), and Department of Surgery (V.M.M.), Mayo Clinic, Rochester, MN
| | - Brian D Lahr
- From the Bruno Balke Biodynamics Laboratory, Department of Kinesiology, University of Wisconsin-Madison (J.N.B., K.B.M.); and Department of Anesthesiology (J.N.B., K.R.M., M.J.J.), College of Medicine and Science (R.E.H.), Department of Physiology and Biomedical Engineering (M.J., V.M.M.), Heath Science Research, Division of Epidemiology and Biostatistics (B.D.L., K.R.B.), and Department of Surgery (V.M.M.), Mayo Clinic, Rochester, MN
| | - Kent R Bailey
- From the Bruno Balke Biodynamics Laboratory, Department of Kinesiology, University of Wisconsin-Madison (J.N.B., K.B.M.); and Department of Anesthesiology (J.N.B., K.R.M., M.J.J.), College of Medicine and Science (R.E.H.), Department of Physiology and Biomedical Engineering (M.J., V.M.M.), Heath Science Research, Division of Epidemiology and Biostatistics (B.D.L., K.R.B.), and Department of Surgery (V.M.M.), Mayo Clinic, Rochester, MN
| | - Michael J Joyner
- From the Bruno Balke Biodynamics Laboratory, Department of Kinesiology, University of Wisconsin-Madison (J.N.B., K.B.M.); and Department of Anesthesiology (J.N.B., K.R.M., M.J.J.), College of Medicine and Science (R.E.H.), Department of Physiology and Biomedical Engineering (M.J., V.M.M.), Heath Science Research, Division of Epidemiology and Biostatistics (B.D.L., K.R.B.), and Department of Surgery (V.M.M.), Mayo Clinic, Rochester, MN
| | - Virginia M Miller
- From the Bruno Balke Biodynamics Laboratory, Department of Kinesiology, University of Wisconsin-Madison (J.N.B., K.B.M.); and Department of Anesthesiology (J.N.B., K.R.M., M.J.J.), College of Medicine and Science (R.E.H.), Department of Physiology and Biomedical Engineering (M.J., V.M.M.), Heath Science Research, Division of Epidemiology and Biostatistics (B.D.L., K.R.B.), and Department of Surgery (V.M.M.), Mayo Clinic, Rochester, MN
| |
Collapse
|
25
|
Liu X, Gerraty RT, Grinband J, Parker D, Razlighi QR. Brain atrophy can introduce age-related differences in BOLD response. Hum Brain Mapp 2017; 38:3402-3414. [PMID: 28397386 PMCID: PMC6866909 DOI: 10.1002/hbm.23597] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 03/10/2017] [Accepted: 03/22/2017] [Indexed: 11/08/2022] Open
Abstract
Use of functional magnetic resonance imaging (fMRI) in studies of aging is often hampered by uncertainty about age-related differences in the amplitude and timing of the blood oxygenation level dependent (BOLD) response (i.e., hemodynamic impulse response function (HRF)). Such uncertainty introduces a significant challenge in the interpretation of the fMRI results. Even though this issue has been extensively investigated in the field of neuroimaging, there is currently no consensus about the existence and potential sources of age-related hemodynamic alterations. Using an event-related fMRI experiment with two robust and well-studied stimuli (visual and auditory), we detected a significant age-related difference in the amplitude of response to auditory stimulus. Accounting for brain atrophy by circumventing spatial normalization and processing the data in subjects' native space eliminated these observed differences. In addition, we simulated fMRI data using age differences in brain morphology while controlling HRF shape. Analyzing these simulated fMRI data using standard image processing resulted in differences in HRF amplitude, which were eliminated when the data were analyzed in subjects' native space. Our results indicate that age-related atrophy introduces inaccuracy in co-registration to standard space, which subsequently appears as attenuation in BOLD response amplitude. Our finding could explain some of the existing contradictory reports regarding age-related differences in the fMRI BOLD responses. Hum Brain Mapp 38:3402-3414, 2017. © 2017 Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- Xueqing Liu
- Biomedical Engineering DepartmentColumbia UniversityNew YorkNew YorkUnited States
| | - Raphael T. Gerraty
- Department of PsychologyColumbia UniversityNew YorkNew YorkUnited States
| | - Jack Grinband
- Department of RadiologyColumbia University Medical CenterNew YorkNew YorkUnited States
| | - David Parker
- Biomedical Engineering DepartmentColumbia UniversityNew YorkNew YorkUnited States
| | - Qolamreza R. Razlighi
- Biomedical Engineering DepartmentColumbia UniversityNew YorkNew YorkUnited States
- Department of NeurologyColumbia University Medical CenterNew YorkNew YorkUnited States
| |
Collapse
|
26
|
Jahanian H, Christen T, Moseley ME, Pajewski NM, Wright CB, Tamura MK, Zaharchuk G. Measuring vascular reactivity with resting-state blood oxygenation level-dependent (BOLD) signal fluctuations: A potential alternative to the breath-holding challenge? J Cereb Blood Flow Metab 2017; 37:2526-2538. [PMID: 27683452 PMCID: PMC5531349 DOI: 10.1177/0271678x16670921] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Measurement of the ability of blood vessels to dilate and constrict, known as vascular reactivity, is often performed with breath-holding tasks that transiently raise arterial blood carbon dioxide (PaCO2) levels. However, following the proper commands for a breath-holding experiment may be difficult or impossible for many patients. In this study, we evaluated two approaches for obtaining vascular reactivity information using blood oxygenation level-dependent signal fluctuations obtained from resting-state functional magnetic resonance imaging data: physiological fluctuation regression and coefficient of variation of the resting-state functional magnetic resonance imaging signal. We studied a cohort of 28 older adults (69 ± 7 years) and found that six of them (21%) could not perform the breath-holding protocol, based on an objective comparison with an idealized respiratory waveform. In the subjects that could comply, we found a strong linear correlation between data extracted from spontaneous resting-state functional magnetic resonance imaging signal fluctuations and the blood oxygenation level-dependent percentage signal change during breath-holding challenge ( R2 = 0.57 and 0.61 for resting-state physiological fluctuation regression and resting-state coefficient of variation methods, respectively). This technique may eliminate the need for subject cooperation, thus allowing the evaluation of vascular reactivity in a wider range of clinical and research conditions in which it may otherwise be impractical.
Collapse
Affiliation(s)
| | - Thomas Christen
- 1 Department of Radiology, Stanford University, Stanford, CA, USA
| | | | - Nicholas M Pajewski
- 2 Department of Biostatistical Sciences, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Clinton B Wright
- 3 Departments of Neurology and Public Health Sciences, and the Neuroscience Program, Evelyn F. McKnight Brain Institute, University of Miami, Miami, FL, USA
| | - Manjula K Tamura
- 4 Geriatric Research and Education Clinical Center, Palo Alto Veterans Affairs Health Care System, Palo Alto, CA, USA.,5 Division of Nephrology, Stanford University, Stanford, CA, USA
| | - Greg Zaharchuk
- 1 Department of Radiology, Stanford University, Stanford, CA, USA
| | | |
Collapse
|
27
|
Urback AL, MacIntosh BJ, Goldstein BI. Cerebrovascular reactivity measured by functional magnetic resonance imaging during breath-hold challenge: A systematic review. Neurosci Biobehav Rev 2017; 79:27-47. [PMID: 28487157 DOI: 10.1016/j.neubiorev.2017.05.003] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Revised: 04/05/2017] [Accepted: 05/02/2017] [Indexed: 10/19/2022]
Abstract
Cerebrovascular reactivity (CVR) is the cerebral hemodynamic response to a vasoactive substance. Breath-hold (BH) induced CVR has the advantage of being non-invasive and easy to implement during magnetic resonance imaging (MRI). We systematically reviewed the literature regarding MRI measurement of BH induced CVR. The literature was searched using MEDLINE with the search terms breath-hold; and MRI or cerebrovascular reactivity. The search yielded 2244 results and 54 articles were included. Between-group comparisons have found that CVR was higher among healthy controls than patients with various pathologies (e.g. sleep apnea, diabetes, hypertension etc.). However, counter-intuitive findings have also been reported, including higher CVR among smokers, sedentary individuals, and patients with schizophrenia vs. CONTROLS Methodological studies have highlighted important measurement characteristics (e.g. normalizing signal to end-tidal CO2), and comparisons of BH induced CVR to non-BH methods. Future studies are warranted to address questions about group differences, treatment response, disease progression, and other salient clinical themes. Standardization of CVR and BH designs is needed to fully exploit the potential of this practical non-invasive method.
Collapse
Affiliation(s)
- Adam L Urback
- Centre for Youth Bipolar Disorder, Sunnybrook Health Sciences Centre 2075 Bayview Ave., FG-53, Toronto, ON, M4N 3M5, Canada; Department of Pharmacology, University of Toronto, Medicine, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada.
| | - Bradley J MacIntosh
- University of Toronto, Department of Medical Biophysics, 101 College Street Suite 15-701, Toronto, ON, M5G 1L7, Canada; Canadian Partnership for Stroke Recovery, Sunnybrook Health Sciences Centre, 2075 Bayview Ave., Room M6 180, Toronto, ON, M4N 3M5, Canada.
| | - Benjamin I Goldstein
- Centre for Youth Bipolar Disorder, Sunnybrook Health Sciences Centre 2075 Bayview Ave., FG-53, Toronto, ON, M4N 3M5, Canada; Department of Pharmacology, University of Toronto, Medicine, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada; Department of Psychiatry, University of Toronto, Medicine,250 College Street, Room 835, Toronto, ON, M5T 1R8, Canada.
| |
Collapse
|
28
|
Grinband J, Steffener J, Razlighi QR, Stern Y. BOLD neurovascular coupling does not change significantly with normal aging. Hum Brain Mapp 2017; 38:3538-3551. [PMID: 28419680 DOI: 10.1002/hbm.23608] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 03/28/2017] [Accepted: 03/28/2017] [Indexed: 12/11/2022] Open
Abstract
Studies of cognitive function that compare the blood oxygenation level dependent (BOLD) signal across age groups often require the assumption that neurovascular coupling does not change with age. Tests of this assumption have produced mixed results regarding the strength of the coupling and its relative time course. Using deconvolution, we found that age does not have a significant effect on the time course of the hemodynamic impulse response function or on the slope of the BOLD versus stimulus duration relationship. These results suggest that in cognitive studies of healthy aging, group differences in BOLD activation are likely due to age-related changes in cognitive-neural interactions and information processing rather than to impairments in neurovascular coupling. Hum Brain Mapp 38:3538-3551, 2017. © 2017 Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- Jack Grinband
- Department of Radiology, Columbia University, New York
| | - Jason Steffener
- Interdisciplinary School of Health Sciences, University of Ottawa, Ontario
| | - Qolamreza R Razlighi
- Department of Neurology, Columbia University, New York.,Department of Biomedical Engineering, Columbia University, New York
| | - Yaakov Stern
- Department of Neurology, Columbia University, New York
| |
Collapse
|
29
|
Nagata K, Yamazaki T, Takano D, Maeda T, Fujimaki Y, Nakase T, Sato Y. Cerebral circulation in aging. Ageing Res Rev 2016; 30:49-60. [PMID: 27484894 DOI: 10.1016/j.arr.2016.06.001] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Revised: 05/31/2016] [Accepted: 06/01/2016] [Indexed: 12/20/2022]
Abstract
Cerebral circulation is known to be protected by the regulatory function against the hypoperfusion that will affect the cognitive function as a result of brain ischemia and energy failure. The regulatory function includes cerebrovascular autoregulation, chemical control, metabolic control, and neurogenic control, and those compensatory mechanisms can be influenced by hypertension, atherosclerosis, cardiac diseases, cerebrovascular diseases and aging. On the other hand, large and/or small infarction, intracranial hemorrhage, subarachnoid hemorrhage, atherosclerosis, amylod angiopathy are also more directly associated with cognitive decline not only in those with vascular cognitive impairment or vascular dementia but also those with Alzheimer's disease.
Collapse
Affiliation(s)
- Ken Nagata
- Department of Neurology, Clinical Research Institute, Yokohama General Hospital, Yokohama, Japan.
| | - Takashi Yamazaki
- Department of Neurology, Clinical Research Institute, Yokohama General Hospital, Yokohama, Japan
| | - Daiki Takano
- Department of Neurology, Clinical Research Institute, Yokohama General Hospital, Yokohama, Japan
| | - Tetsuya Maeda
- Department of Neurology and Gerontology, Iwate Medical University, Morioka, Japan
| | - Yumi Fujimaki
- Department of Neurology, Research Institute for Brain and Blood Vessels, Akita, Japan
| | - Taizen Nakase
- Department of Neurology, Research Institute for Brain and Blood Vessels, Akita, Japan
| | - Yuichi Sato
- Department of Neurology, Noshiro Yamamoto Medical Association Hospital, Noshiro, Japan
| |
Collapse
|
30
|
Hypercapnic evaluation of vascular reactivity in healthy aging and acute stroke via functional MRI. NEUROIMAGE-CLINICAL 2016; 12:173-9. [PMID: 27437178 PMCID: PMC4939388 DOI: 10.1016/j.nicl.2016.06.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 05/26/2016] [Accepted: 06/22/2016] [Indexed: 11/23/2022]
Abstract
Functional MRI (fMRI) is well-established for the study of brain function in healthy populations, although its clinical application has proven more challenging. Specifically, cerebrovascular reactivity (CVR), which allows the assessment of the vascular response that serves as the basis for fMRI, has been shown to be reduced in healthy aging as well as in a range of diseases, including chronic stroke. However, the timing of when this occurs relative to the stroke event is unclear. We used a breath-hold fMRI task to evaluate CVR across gray matter in a group of acute stroke patients (< 10 days from stroke; N = 22) to address this question. These estimates were compared with those from both age-matched (N = 22) and younger (N = 22) healthy controls. As expected, young controls had the greatest mean CVR, as indicated by magnitude and extent of fMRI activation; however, stroke patients did not differ from age-matched controls. Moreover, the ipsilesional and contralesional hemispheres of stroke patients did not differ with respect to any of these measures. These findings suggest that fMRI remains a valid tool within the first few days of a stroke, particularly for group fMRI studies in which findings are compared with healthy subjects of similar age. However, given the relatively high variability in CVR observed in our stroke sample, caution is warranted when interpreting fMRI data from individual patients or a small cohort. We conclude that a breath-hold task can be a useful addition to functional imaging protocols for stroke patients. Breath-holding can be used to assess the validity of fMRI in stroke patients. Vascular reactivity, estimated by breath-hold fMRI, was greatest in young controls. Acute stroke patients and age-matched controls had similar vascular reactivity. Modeling the breath-hold response on an individual basis can improve results.
Collapse
|
31
|
Haight TJ, Bryan RN, Erus G, Davatzikos C, Jacobs DR, D'Esposito M, Lewis CE, Launer LJ. Vascular risk factors, cerebrovascular reactivity, and the default-mode brain network. Neuroimage 2015; 115:7-16. [PMID: 25917517 PMCID: PMC4469180 DOI: 10.1016/j.neuroimage.2015.04.039] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Revised: 04/14/2015] [Accepted: 04/19/2015] [Indexed: 01/12/2023] Open
Abstract
Cumulating evidence from epidemiologic studies implicates cardiovascular health and cerebrovascular function in several brain diseases in late life. We examined vascular risk factors with respect to a cerebrovascular measure of brain functioning in subjects in mid-life, which could represent a marker of brain changes in later life. Breath-hold functional MRI (fMRI) was performed in 541 women and men (mean age 50.4 years) from the Coronary Artery Risk Development in Young Adults (CARDIA) Brain MRI sub-study. Cerebrovascular reactivity (CVR) was quantified as percentage change in blood-oxygen level dependent (BOLD) signal in activated voxels, which was mapped to a common brain template and log-transformed. Mean CVR was calculated for anatomic regions underlying the default-mode network (DMN) - a network implicated in AD and other brain disorders - in addition to areas considered to be relatively spared in the disease (e.g. occipital lobe), which were utilized as reference regions. Mean CVR was significantly reduced in the posterior cingulate/precuneus (β=-0.063, 95% CI: -0.106, -0.020), anterior cingulate (β=-0.055, 95% CI: -0.101, -0.010), and medial frontal lobe (β=-0.050, 95% CI: -0.092, -0.008) relative to mean CVR in the occipital lobe, after adjustment for age, sex, race, education, and smoking status, in subjects with pre-hypertension/hypertension compared to normotensive subjects. By contrast, mean CVR was lower, but not significantly, in the inferior parietal lobe (β=-0.024, 95% CI: -0.062, 0.014) and the hippocampus (β=-0.006, 95% CI: -0.062, 0.050) relative to mean CVR in the occipital lobe. Similar results were observed in subjects with diabetes and dyslipidemia compared to those without these conditions, though the differences were non-significant. Reduced CVR may represent diminished vascular functionality for the DMN for individuals with prehypertension/hypertension in mid-life, and may serve as a preclinical marker for brain dysfunction in later life.
Collapse
Affiliation(s)
- Thaddeus J Haight
- Laboratory of Epidemiology and Population Sciences, National Institute on Aging, 7201 Wisconsin Avenue, Room 3C309, Bethesda, MD 20814, USA.
| | - R Nick Bryan
- Department of Radiology, University of Pennsylvania, 3600 Market St., Philadelphia, PA 19104, USA
| | - Guray Erus
- Department of Radiology, University of Pennsylvania, 3600 Market St., Philadelphia, PA 19104, USA
| | - Christos Davatzikos
- Department of Radiology, University of Pennsylvania, 3600 Market St., Philadelphia, PA 19104, USA
| | - David R Jacobs
- Division of Epidemiology and Community Health, University of Minnesota, 1300 S. 2nd Street, Suite 300, Minneapolis, MN, USA
| | - Mark D'Esposito
- Helen Wills Neuroscience Institute, University of California-Berkeley, 132 Barker Hall, Berkeley, CA, USA
| | - Cora E Lewis
- Department of Medicine, Division of Preventive Medicine, University of Alabama, Medical Towers 614, 1717 11th Avenue South, Birmingham, AL, USA
| | - Lenore J Launer
- Laboratory of Epidemiology and Population Sciences, National Institute on Aging, 7201 Wisconsin Avenue, Room 3C309, Bethesda, MD 20814, USA
| |
Collapse
|
32
|
Boudiaf N, Attyé A, Warnking JM, Troprès I, Lamalle L, Pietras J, Krainik A. BOLD fMRI of cerebrovascular reactivity in the middle cerebral artery territory: A 100 volunteers' study. J Neuroradiol 2015; 42:338-44. [PMID: 26031884 DOI: 10.1016/j.neurad.2015.04.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 03/26/2015] [Accepted: 04/05/2015] [Indexed: 11/15/2022]
Abstract
BACKGROUND AND PURPOSE The assessment of cerebrovascular reactivity (CVR) has shown promising results for its use in medical diagnosis and prognosis, especially in patients suffering from severe intracranial arterial stenosis. However, its quantification remains uncertain because of a large variability inherent in brain anatomy and in methodological settings. To overcome this variability, we provide lateralization index (LI) values for CVR within the middle cerebral artery territory to detect CVR impairment. MATERIALS AND METHODS We assessed CVR in 100 volunteers (41 females; 47.52 ± 21.58 years) without cervico-encephalic arterial stenosis using BOLD-fMRI contrast with a block-design hypercapnic challenge. Averaged end-tidal CO2 was used as a physiological regressor for statistical analyses with a general linear model. We measured %BOLD signal-change in segmented gray matter regions of interest in the middle cerebral artery territory (MCA). We calculated a laterality index according to the following formula: LI=(CVRleft-CVRright)/(CVRleft+CVRright). We tested the effects of methodological settings (i.e. hypercapnic gas, gas administration means, MR acquisition and sex) on %BOLD signal change and LI values with analysis of variance. RESULTS No adverse effects of the hypercapnic challenge were reported. LI values were independent of experimental conditions. Mean LI calculated in MCA territories was 0.016 ± 0.031, giving the lower and upper limits of 95% (m ± 2SD) of this population distribution at]-0.05; 0.08[. CONCLUSION LI can effectively help us to overcome measurement variabilities. Therefore, it can be used to detect abnormal asymmetries in CVR and identify patients at higher risk of ischemic stroke.
Collapse
Affiliation(s)
- Naïla Boudiaf
- Université Grenoble Alpes 3bis, CNRS, LPNC, 38000 Grenoble, France; Université Savoie 3, LPNC, 73000 Chambéry, France.
| | - Arnaud Attyé
- Inserm, université Grenoble Alpes, GIN, CHU de Grenoble, 38000 Grenoble, France; Department of Neuroradiology and MRI, University Hospital of Grenoble-IFR1, Grenoble, France
| | - Jan M Warnking
- Inserm, université Grenoble Alpes, GIN, CHU de Grenoble, 38000 Grenoble, France
| | - Irène Troprès
- Inserm, université Grenoble Alpes, GIN, CHU de Grenoble, 38000 Grenoble, France; Inserm, université Grenoble Alpes, CNRS, IRMaGe, CHU de Grenoble, 38000 Grenoble, France
| | - Laurent Lamalle
- Inserm, université Grenoble Alpes, CNRS, IRMaGe, CHU de Grenoble, 38000 Grenoble, France
| | - Johan Pietras
- Inserm, université Grenoble Alpes, CNRS, IRMaGe, CHU de Grenoble, 38000 Grenoble, France
| | - Alexandre Krainik
- Inserm, université Grenoble Alpes, GIN, CHU de Grenoble, 38000 Grenoble, France; Inserm, université Grenoble Alpes, CNRS, IRMaGe, CHU de Grenoble, 38000 Grenoble, France; Department of Neuroradiology and MRI, University Hospital of Grenoble-IFR1, Grenoble, France
| |
Collapse
|
33
|
Tchistiakova E, Crane DE, Mikulis DJ, Anderson ND, Greenwood CE, Black SE, MacIntosh BJ. Vascular risk factor burden correlates with cerebrovascular reactivity but not resting state coactivation in the default mode network. J Magn Reson Imaging 2015; 42:1369-76. [PMID: 25884110 DOI: 10.1002/jmri.24917] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 03/30/2015] [Indexed: 01/06/2023] Open
Abstract
PURPOSE White matter hyperintensities (WMH) are prevalent among older adults and are often associated with cognitive decline and increased risk of stroke and dementia. Vascular risk factors (VRFs) are linked to WMH, yet the impact of multiple VRFs on gray matter function is still unclear. The goal of this study was to test for associations between the number of VRFs and cerebrovascular reactivity (CVR) and resting state (RS) coactivation among individuals with WMH. MATERIALS AND METHODS Twenty-nine participants with suspected WMH were grouped based on the number of VRFs (subgroups: 0, 1, or ≥2). CVR and RS coactivation were measured with blood oxygenation level-dependent (BOLD) imaging on a 3T magnetic resonance imaging (MRI) system during hypercapnia and rest, respectively. Default-mode (DMN), sensory-motor, and medial-visual networks, generated using independent component analysis of RS-BOLD, were selected as networks of interest (NOIs). CVR-BOLD was analyzed using two methods: 1) a model-based approach using CO2 traces, and 2) a dual-regression (DR) approach using NOIs as spatial inputs. Average CVR and RS coactivations within NOIs were compared between VRF subgroups. A secondary analysis investigated the correlation between CVR and RS coactivation. RESULTS VRF subgroup differences were detected using DR-based CVR in the DMN (F20,2 = 5.17, P = 0.015) but not the model-based CVR nor RS coactivation. DR-based CVR was correlated with RS coactivation in the DMN (r(2) = 0.28, P = 0.006) but not the sensory-motor nor medial-visual NOIs. CONCLUSION In individuals with WMH, CVR in the DMN was inversely associated with the number of VRFs and correlated with RS coactivation.
Collapse
Affiliation(s)
- Ekaterina Tchistiakova
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.,Heart and Stroke Foundation Canadian Partnership for Stroke Recovery, Toronto, Ontario, Canada.,Brain Sciences Research Program, Toronto, Ontario, Canada
| | - David E Crane
- Heart and Stroke Foundation Canadian Partnership for Stroke Recovery, Toronto, Ontario, Canada.,Brain Sciences Research Program, Toronto, Ontario, Canada
| | - David J Mikulis
- Department of Medical Imaging, University of Toronto, Toronto Western Hospital, Toronto, Ontario, Canada
| | - Nicole D Anderson
- Department of Psychology, University of Toronto, Toronto, Ontario, Canada.,Rotman Research Institute, Toronto, Ontario, Canada.,Department of Medicine (Psychiatry), University of Toronto, Toronto, Ontario, Canada
| | - Carol E Greenwood
- Rotman Research Institute, Toronto, Ontario, Canada.,Department of Nutritional Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Sandra E Black
- Heart and Stroke Foundation Canadian Partnership for Stroke Recovery, Toronto, Ontario, Canada.,Brain Sciences Research Program, Toronto, Ontario, Canada.,Rotman Research Institute, Toronto, Ontario, Canada.,Department of Medicine (Neurology), Sunnybrook Health Sciences Centre and University of Toronto, Toronto, Ontario, Canada
| | - Bradley J MacIntosh
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.,Heart and Stroke Foundation Canadian Partnership for Stroke Recovery, Toronto, Ontario, Canada.,Brain Sciences Research Program, Toronto, Ontario, Canada
| |
Collapse
|
34
|
Agreement and repeatability of vascular reactivity estimates based on a breath-hold task and a resting state scan. Neuroimage 2015; 113:387-96. [PMID: 25795342 PMCID: PMC4441043 DOI: 10.1016/j.neuroimage.2015.03.004] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 02/27/2015] [Accepted: 03/03/2015] [Indexed: 12/02/2022] Open
Abstract
FMRI BOLD responses to changes in neural activity are influenced by the reactivity of the vasculature. By complementing a task-related BOLD acquisition with a vascular reactivity measure obtained through breath-holding or hypercapnia, this unwanted variance can be statistically reduced in the BOLD responses of interest. Recently, it has been suggested that vascular reactivity can also be estimated using a resting state scan. This study aimed to compare three breath-hold based analysis approaches (block design, sine–cosine regressor and CO2 regressor) and a resting state approach (CO2 regressor) to measure vascular reactivity. We tested BOLD variance explained by the model and repeatability of the measures. Fifteen healthy participants underwent a breath-hold task and a resting state scan with end-tidal CO2 being recorded during both. Vascular reactivity was defined as CO2-related BOLD percent signal change/mm Hg change in CO2. Maps and regional vascular reactivity estimates showed high repeatability when the breath-hold task was used. Repeatability and variance explained by the CO2 trace regressor were lower for the resting state data based approach, which resulted in highly variable measures of vascular reactivity. We conclude that breath-hold based vascular reactivity estimations are more repeatable than resting-based estimates, and that there are limitations with replacing breath-hold scans by resting state scans for vascular reactivity assessment.
Collapse
|
35
|
Functional changes in the human auditory cortex in ageing. PLoS One 2015; 10:e0116692. [PMID: 25734519 PMCID: PMC4348517 DOI: 10.1371/journal.pone.0116692] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Accepted: 12/14/2014] [Indexed: 11/19/2022] Open
Abstract
Hearing loss, presbycusis, is one of the most common sensory declines in the ageing population. Presbycusis is characterised by a deterioration in the processing of temporal sound features as well as a decline in speech perception, thus indicating a possible central component. With the aim to explore the central component of presbycusis, we studied the function of the auditory cortex by functional MRI in two groups of elderly subjects (>65 years) and compared the results with young subjects (<lt;30 years). The elderly group with expressed presbycusis (EP) differed from the elderly group with mild presbycusis (MP) in hearing thresholds measured by pure tone audiometry, presence and amplitudes of transient otoacoustic emissions (TEOAE) and distortion-product oto-acoustic emissions (DPOAE), as well as in speech-understanding under noisy conditions. Acoustically evoked activity (pink noise centered around 350 Hz, 700 Hz, 1.5 kHz, 3 kHz, 8 kHz), recorded by BOLD fMRI from an area centered on Heschl’s gyrus, was used to determine age-related changes at the level of the auditory cortex. The fMRI showed only minimal activation in response to the 8 kHz stimulation, despite the fact that all subjects heard the stimulus. Both elderly groups showed greater activation in response to acoustical stimuli in the temporal lobes in comparison with young subjects. In addition, activation in the right temporal lobe was more expressed than in the left temporal lobe in both elderly groups, whereas in the young control subjects (YC) leftward lateralization was present. No statistically significant differences in activation of the auditory cortex were found between the MP and EP groups. The greater extent of cortical activation in elderly subjects in comparison with young subjects, with an asymmetry towards the right side, may serve as a compensatory mechanism for the impaired processing of auditory information appearing as a consequence of ageing.
Collapse
|
36
|
Tsvetanov KA, Henson RNA, Tyler LK, Davis SW, Shafto MA, Taylor JR, Williams N, Cam-Can, Rowe JB. The effect of ageing on fMRI: Correction for the confounding effects of vascular reactivity evaluated by joint fMRI and MEG in 335 adults. Hum Brain Mapp 2015; 36:2248-69. [PMID: 25727740 PMCID: PMC4730557 DOI: 10.1002/hbm.22768] [Citation(s) in RCA: 133] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Revised: 02/04/2015] [Accepted: 02/05/2015] [Indexed: 11/08/2022] Open
Abstract
In functional magnetic resonance imaging (fMRI) research one is typically interested in neural activity. However, the blood‐oxygenation level‐dependent (BOLD) signal is a composite of both neural and vascular activity. As factors such as age or medication may alter vascular function, it is essential to account for changes in neurovascular coupling when investigating neurocognitive functioning with fMRI. The resting‐state fluctuation amplitude (RSFA) in the fMRI signal (rsfMRI) has been proposed as an index of vascular reactivity. The RSFA compares favourably with other techniques such as breath‐hold and hypercapnia, but the latter are more difficult to perform in some populations, such as older adults. The RSFA is therefore a candidate for use in adjusting for age‐related changes in vascular reactivity in fMRI studies. The use of RSFA is predicated on its sensitivity to vascular rather than neural factors; however, the extent to which each of these factors contributes to RSFA remains to be characterized. The present work addressed these issues by comparing RSFA (i.e., rsfMRI variability) to proxy measures of (i) cardiovascular function in terms of heart rate (HR) and heart rate variability (HRV) and (ii) neural activity in terms of resting state magnetoencephalography (rsMEG). We derived summary scores of RSFA, a sensorimotor task BOLD activation, cardiovascular function and rsMEG variability for 335 healthy older adults in the population‐based Cambridge Centre for Ageing and Neuroscience cohort (Cam‐CAN; http://www.cam-can.com). Mediation analysis revealed that the effects of ageing on RSFA were significantly mediated by vascular factors, but importantly not by the variability in neuronal activity. Furthermore, the converse effects of ageing on the rsMEG variability were not mediated by vascular factors. We then examined the effect of RSFA scaling of task‐based BOLD in the sensorimotor task. The scaling analysis revealed that much of the effects of age on task‐based activation studies with fMRI do not survive correction for changes in vascular reactivity, and are likely to have been overestimated in previous fMRI studies of ageing. The results from the mediation analysis demonstrate that RSFA is modulated by measures of vascular function and is not driven solely by changes in the variance of neural activity. Based on these findings we propose that the RSFA scaling method is articularly useful in large scale and longitudinal neuroimaging studies of ageing, or with frail participants, where alternative measures of vascular reactivity are impractical. Hum Brain Mapp 36:2248–2269, 2015. © 2015 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- Kamen A Tsvetanov
- Centre for Speech, Language and the Brain, Department of Psychology, University of Cambridge, Cambridge, United Kingdom
| | | | | | | | | | | | | | | | | |
Collapse
|
37
|
Imai R, Hayashida K, Nakano H, Morioka S. Brain Activity Associated with the Illusion of Motion Evoked by Different Vibration Stimulation Devices: An fNIRS Study. J Phys Ther Sci 2014; 26:1115-9. [PMID: 25140108 PMCID: PMC4135209 DOI: 10.1589/jpts.26.1115] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 02/07/2014] [Indexed: 11/24/2022] Open
Abstract
[Purpose] A number of different stimulation devices are used in basic and clinical research studies, and their frequencies of use vary. However, whether or not they are equally effective has not been investigated. The purpose of the present study was to investigate neural activity in the brain during the illusion of motion evoked by stimulating the tendons of the wrist extensor muscles using various vibration devices. [Subjects] Twelve right-handed university students with no history of nervous system disorder or orthopedic disease participated in the study. [Methods] The wrist extensor tendon was stimulated using 3 different devices: 1) a vibration stimulation device (SL-0105 LP; Asahi Seisakusho Co., Ltd., Saitama, Japan), frequency 80 Hz; 2) a handy massager (YCM-20; Yamazen Corporation, Osaka, Japan), frequency 70 Hz; and 3) a handy massager (Thrive MD-01; Thrive Co., Ltd., Osaka, Japan), frequency 91.7 Hz. Brain activity was recorded during stimulation by using functional near-infrared spectroscopy. [Results] Increased neural activity was observed in both the premotor cortices and the parietal region in both hemispheres in all 3 cases. The level and localization of neural activity was comparable for all 3 stimulation devices used. [Conclusion] This suggests that subjects experience the illusion of motion while the tendon is being stimulated using any vibration device.
Collapse
Affiliation(s)
- Ryota Imai
- Department of Neurorehabilitation, Graduate School of Health Sciences, Kio University, Japan ; Department of Rehabilitation, Kawachi General Hospital, Japan
| | - Kazuki Hayashida
- Department of Physical Therapy, Faculty of Health and Science, Kio University, Japan
| | - Hideki Nakano
- Department of Neurorehabilitation, Graduate School of Health Sciences, Kio University, Japan ; Queensland Brain Institute, The University of Queensland, Australia ; Japan Society for the Promotion of Science, Japan
| | - Shu Morioka
- Department of Neurorehabilitation, Graduate School of Health Sciences, Kio University, Japan
| |
Collapse
|
38
|
Dalmases M, Torres M, Márquez-Kisinousky L, Almendros I, Planas AM, Embid C, Martínez-Garcia MÁ, Navajas D, Farré R, Montserrat JM. Brain tissue hypoxia and oxidative stress induced by obstructive apneas is different in young and aged rats. Sleep 2014; 37:1249-56. [PMID: 25061253 DOI: 10.5665/sleep.3848] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
STUDY OBJECTIVES To test the hypotheses that brain oxygen partial pressure (PtO2) in response to obstructive apneas changes with age and that it might lead to different levels of cerebral tissue oxidative stress. DESIGN Prospective controlled animal study. SETTING University laboratory. PARTICIPANTS Sixty-four male Wistar rats: 32 young (3 mo old) and 32 aged (18 mo). INTERVENTIONS Protocol 1: Twenty-four animals were subjected to obstructive apneas (50 apneas/h, lasting 15 sec each) or to sham procedure for 50 min. Protocol 2: Forty rats were subjected to obstructive apneas or sham procedure for 4 h. MEASUREMENTS AND RESULTS Protocol 1: Real-time PtO2 measurements were performed using a fast-response oxygen microelectrode. During successive apneas cerebral cortex PtO2 presented a different pattern in the two age groups; there was a fast increase in young rats, whereas it remained without significant changes between the beginning and the end of the protocol in the aged group. Protocol 2: Brain oxidative stress assessed by lipid peroxidation increased after apneas in young rats (1.34 ± 0.17 nmol/mg of protein) compared to old ones (0.63 ± 0.03 nmol/mg), where a higher expression of antioxidant enzymes was observed. CONCLUSIONS The results suggest that brain oxidative stress in aged rats is lower than in young rats in response to recurrent apneas, mimicking obstructive sleep apnea. This could be due to the different PtO2 response observed between age groups and the increased antioxidant expression in aged rats. CITATION Dalmases M, Torres M, Márquez-Kisinousky L, Almendros I, Planas AM, Embid C, Martínez-Garcia MA, Navajas D, Farré R, Montserrat JM. Brain tissue hypoxia and oxidative stress induced by obstructive apneas is different in young and aged rats.
Collapse
Affiliation(s)
- Mireia Dalmases
- Laboratori de la Son, Pneumologia, Hospital Clinic-Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain ; CIBER Enfermedades Respiratorias, Bunyola, Spain
| | - Marta Torres
- Laboratori de la Son, Pneumologia, Hospital Clinic-Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain ; CIBER Enfermedades Respiratorias, Bunyola, Spain
| | | | - Isaac Almendros
- Laboratori de la Son, Pneumologia, Hospital Clinic-Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain ; CIBER Enfermedades Respiratorias, Bunyola, Spain
| | - Anna M Planas
- Departament d'Isquemia cerebral y neurodegeneració, IIBB-CSIC-IDIBAPS, Barcelona, Spain
| | - Cristina Embid
- Laboratori de la Son, Pneumologia, Hospital Clinic-Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain ; CIBER Enfermedades Respiratorias, Bunyola, Spain
| | | | - Daniel Navajas
- CIBER Enfermedades Respiratorias, Bunyola, Spain ; Unitat de Biofisica i Bioenginyeria, Facultat de Medicina, Universitat de Barcelona-IDIBAPS, Barcelona, Spain ; Institut de Bioenginyeria de Catalunya, Barcelona, Spain
| | - Ramon Farré
- CIBER Enfermedades Respiratorias, Bunyola, Spain ; Unitat de Biofisica i Bioenginyeria, Facultat de Medicina, Universitat de Barcelona-IDIBAPS, Barcelona, Spain
| | - Josep Maria Montserrat
- Laboratori de la Son, Pneumologia, Hospital Clinic-Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain ; CIBER Enfermedades Respiratorias, Bunyola, Spain
| |
Collapse
|
39
|
Gonzales MM, Tarumi T, Mumford JA, Ellis RC, Hungate JR, Pyron M, Tanaka H, Haley AP. Greater BOLD response to working memory in endurance-trained adults revealed by breath-hold calibration. Hum Brain Mapp 2014; 35:2898-910. [PMID: 24038949 PMCID: PMC6869752 DOI: 10.1002/hbm.22372] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Revised: 07/02/2013] [Accepted: 07/08/2013] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND Cardiorespiratory fitness is associated with increased frontal and parietal activation during executive function tasks. While these findings suggest fitness-related enhancement of neuronal response, the utility of functional magnetic resonance imaging (fMRI) may be limited by potential fitness-related differences in global vascular reactivity. The aim of this study was to determine if highly fit adults display differential activation during working memory after calibration for vascular reactivity relative to their sedentary counterparts. METHODS Thirty-two endurance-trained and 24 sedentary adults, aged 40-65 years, completed a 2-Back verbal working memory task and a breath-hold challenge during fMRI. Group differences in blood oxygen level-dependent (BOLD) response during working memory were examined across the whole brain and in a priori regions of interest (ROI) before and after breath-hold calibration using non-parametric permutation testing. Multiple regression was used to explore the association between cardiorespiratory fitness (VO2 max), age, and calibrated 2-Back-related activation within the one a priori ROI with significant group effects. RESULTS In comparison to the endurance-trained group, the sedentary group exhibited greater BOLD signal changes in response to the breath-hold task. After, but not before calibration, the endurance-trained group displayed significantly higher 2-Back-related activation in the right middle frontal gyrus (P = 0.049). Older age predicted lower 2-Back-related activation (ß = -0.308, P = 0.031), whereas fitness predicted higher activation (ß = 0.372, P = 0.021) in this region. CONCLUSIONS Breath-hold calibration increased detection of working memory-related BOLD response differences between sedentary and endurance-trained adults. Moreover, cardiorespiratory fitness appeared to mitigate age-related changes in BOLD during working memory in this region.
Collapse
Affiliation(s)
- Mitzi M. Gonzales
- Department of PsychologyThe University of Texas at AustinAustinTexas
| | - Takashi Tarumi
- Department of Kinesiology and Health EducationThe University of Texas at AustinAustinTexas
| | - Jeanette A. Mumford
- Department of PsychologyThe University of Texas at AustinAustinTexas
- University of Texas Imaging Research CenterAustinTexas
| | - Ryan C. Ellis
- Department of PsychologyThe University of Texas at AustinAustinTexas
| | | | - Martha Pyron
- Department of Kinesiology and Health EducationThe University of Texas at AustinAustinTexas
- Medicine in Motion13805 Research Blvd, Ste 150AustinTexas
| | - Hirofumi Tanaka
- Department of Kinesiology and Health EducationThe University of Texas at AustinAustinTexas
| | - Andreana P. Haley
- Department of PsychologyThe University of Texas at AustinAustinTexas
- University of Texas Imaging Research CenterAustinTexas
| |
Collapse
|
40
|
Tchistiakova E, Anderson ND, Greenwood CE, MacIntosh BJ. Combined effects of type 2 diabetes and hypertension associated with cortical thinning and impaired cerebrovascular reactivity relative to hypertension alone in older adults. NEUROIMAGE-CLINICAL 2014; 5:36-41. [PMID: 24967157 PMCID: PMC4066185 DOI: 10.1016/j.nicl.2014.05.020] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Revised: 05/17/2014] [Accepted: 05/30/2014] [Indexed: 10/31/2022]
Abstract
OBJECTIVE Type 2 diabetes mellitus is characterized by metabolic dysregulation in the form of hyperglycemia and insulin resistance and can have a profound impact on brain structure and vasculature. The primary aim of this study was to identify brain regions where the combined effects of type 2 diabetes and hypertension on brain health exceed those of hypertension alone. A secondary objective was to test whether vascular impairment and structural brain measures in this population are associated with cognitive function. RESEARCH DESIGN AND METHODS We enrolled 18 diabetic participants with hypertension (HTN + T2DM, 7 women, 71.8 ± 5.6 years) and 22 participants with hypertension only (HTN, 12 women, 73.4 ± 6.2 years). Cerebrovascular reactivity (CVR) was assessed using blood oxygenation level dependent (BOLD) MRI during successive breath holds. Gray matter structure was evaluated using cortical thickness (CThk) measures estimated from T1-weighted images. Analyses of cognitive and blood data were also performed. RESULTS Compared to HTN, HTN + T2DM had decreased CVR and CThk in a spatially overlapping region of the right occipital lobe (P < 0.025); CVR group differences were more expansive and included bilateral occipito-parietal areas (P < 0.025). Whereas CVR showed no significant associations with measures of cognitive function (P > 0.05), CThk in the right lingual gyrus ROI and regions resulting from a vertex-wise analysis (including posterior cingulate, precuneus, superior and middle frontal, and middle and inferior temporal regions (P < 0.025) were associated with executive function. CONCLUSIONS Individuals with T2DM and HTN showed decreased CVR and CThk compared to age-matched HTN controls. This study identifies brain regions that are impacted by the combined effects of comorbid T2DM and HTN conditions, with new evidence that the corresponding cortical thinning may contribute to cognitive decline.
Collapse
Key Words
- 3DMPRAGE, three-dimensional magnetization-prepared rapid gradient-echo
- BH, breath hold
- BOLD, blood oxygenation level dependent imaging
- CThk, cortical thickness
- CVR, cerebrovascular reactivity
- Cerebrovascular reactivity
- Cortical thickness
- Diabetes
- FLAIR, fluid attenuation inversion recovery
- FLEX, fuzzy lesion extractor
- HBA1C, hemoglobin A1C
- HTN, hypertension
- Hypertension
- T2DM, type 2 diabetes mellitus
- TICS, Telephone Interview for Cognitive Status
- WMH, white matter hyperintensities
Collapse
Affiliation(s)
- Ekaterina Tchistiakova
- Department of Medical Biophysics, University of Toronto, 610 University Ave., Toronto, ON M5G 2M9, Canada ; Heart and Stroke Foundation Canadian Partnership for Stroke Recovery, 2075 Bayview Ave., Toronto, ON M4N 3M5, Canada ; Brain Sciences Research Program, Sunnybrook Research Institute, 2075 Bayview Ave., Toronto, ON M4N 3M5, Canada
| | - Nicole D Anderson
- Department of Psychology, University of Toronto, 100 St. George Street, Toronto, ON M5S 1A8, Canada ; Rotman Research Institute, Baycrest, 3560 Bathurst Street, Toronto, ON M6A 2E1, Canada ; Department of Medicine (Psychiatry), University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada
| | - Carol E Greenwood
- Rotman Research Institute, Baycrest, 3560 Bathurst Street, Toronto, ON M6A 2E1, Canada ; Department of Nutritional Sciences, University of Toronto, FitzGerald Building, 150 College Street, Toronto, ON M5S 3E2, Canada
| | - Bradley J MacIntosh
- Department of Medical Biophysics, University of Toronto, 610 University Ave., Toronto, ON M5G 2M9, Canada ; Heart and Stroke Foundation Canadian Partnership for Stroke Recovery, 2075 Bayview Ave., Toronto, ON M4N 3M5, Canada ; Brain Sciences Research Program, Sunnybrook Research Institute, 2075 Bayview Ave., Toronto, ON M4N 3M5, Canada
| |
Collapse
|
41
|
Intrinsic functional connectivity networks in healthy elderly subjects: a multiparametric approach with structural connectivity analysis. BIOMED RESEARCH INTERNATIONAL 2014; 2014:947252. [PMID: 24971361 PMCID: PMC4058120 DOI: 10.1155/2014/947252] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Revised: 05/01/2014] [Accepted: 05/03/2014] [Indexed: 12/11/2022]
Abstract
Intrinsic functional connectivity magnetic resonance imaging (iFCMRI) provides an encouraging approach for mapping large-scale intrinsic connectivity networks (ICNs) in the “resting” brain. Structural connections as measured by diffusion tensor imaging (DTI) are a major constraint on the identified ICNs. This study aimed at the combined investigation of ten well-defined ICNs in healthy elderly subjects at single subject level as well as at the group level, together with the underlying structural connectivity. IFCMRI and DTI data were acquired in twelve subjects (68 ± 7 years) at a 3T scanner and were studied using the tensor imaging and fiber tracking software package. The seed-based iFCMRI analysis approach was comprehensively performed with DTI analysis, following standardized procedures including an 8-step processing of iFCMRI data. Our findings demonstrated robust ICNs at the single subject level and conclusive brain maps at the group level in the healthy elderly sample, supported by the complementary fiber tractography. The findings demonstrated here provide a methodological framework for future comparisons of pathological (e.g., neurodegenerative) conditions with healthy controls on the basis of multiparametric functional connectivity mapping.
Collapse
|
42
|
Prilipko O, Huynh N, Thomason ME, Kushida CA, Guilleminault C. An fMRI study of cerebrovascular reactivity and perfusion in obstructive sleep apnea patients before and after CPAP treatment. Sleep Med 2014; 15:892-8. [PMID: 24916094 DOI: 10.1016/j.sleep.2014.04.004] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Revised: 04/05/2014] [Accepted: 04/10/2014] [Indexed: 10/25/2022]
Abstract
OBJECTIVE Cerebrovascular reactivity is impaired in patients suffering from obstructive sleep apnea syndrome (OSAS) as demonstrated by transcranial Doppler studies. We use magnetic resonance imaging techniques to investigate the anatomical distribution of cerebrovascular reactivity changes in patients with OSAS, as well as their evolution after therapeutic and sham continuous positive airway pressure (CPAP) treatment. METHODS Twenty-three men with moderate or severe obstructive sleep apnea were compared to a healthy control group (n=7) using a breath-holding functional magnetic resonance imaging task and the flow-sensitive alternating inversion recovery (FAIR) imaging before and after 2 months of therapeutic (active) or sub-therapeutic (sham) CPAP treatment. RESULTS Significantly higher cerebrovascular reactivity was found in healthy controls as compared to patients in bilateral cortical and subcortical brain regions. Cerebrovascular reactivity increased with therapeutic CPAP in the thalamus and decreased with sham CPAP in medial frontal regions in OSAS patients. Duration of nocturnal hypoxemia and body mass index negatively correlated with cerebrovascular reactivity, particularly in the medial temporal lobe structures, suggesting a possible pathophysiological mechanism for hippocampal injury. There was no difference in perfusion between patients and control group, and no effect of CPAP or sham-CPAP treatment on perfusion in patients. CONCLUSIONS Observed cerebrovascular reactivity changes were neither homogeneous throughout the brain nor followed vascular territories, but rather corresponded to underlying neuronal networks, establishing a relationship between cerebrovascular reactivity and surrounding neuronal activity.
Collapse
Affiliation(s)
- Olga Prilipko
- Stanford University Sleep Clinic and Center for Human Sleep Research, Redwood City, CA, USA.
| | - Nelly Huynh
- Stanford University Sleep Clinic and Center for Human Sleep Research, Redwood City, CA, USA
| | - Moriah E Thomason
- Department of Pediatrics, Wayne State University School of Medicine, Detroit, MI, USA; Merrill Palmer Skillman Institute for Child and Family Development, Wayne State University, Detroit, MI, USA
| | - Clete A Kushida
- Stanford University Sleep Clinic and Center for Human Sleep Research, Redwood City, CA, USA
| | | |
Collapse
|
43
|
Chen YC, Chen CC, Decety J, Cheng Y. Aging is associated with changes in the neural circuits underlying empathy. Neurobiol Aging 2013; 35:827-36. [PMID: 24211010 DOI: 10.1016/j.neurobiolaging.2013.10.080] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Revised: 09/26/2013] [Accepted: 10/16/2013] [Indexed: 12/19/2022]
Abstract
Although the neurodevelopment of empathy from childhood to adolescence has been documented, no study has yet examined it across a life span aging perspective. Sixty-five healthy participants from 3 age groups (young, middle-aged, old) underwent functional magnetic resonance imaging while presented with visual stimuli depicting body parts being injured, either accidentally by oneself or intentionally by another, thus isolating pain and agency as 2 variables of interest. Older adults reported less dispositional emotional empathy as assessed by the interpersonal reactivity index, and their unpleasantness ratings were more sensitive to intentional harm. The response in anterior insula and anterior mid-cingulate cortex to others' pain, indicative of emotional empathy, showed an age-related decline, whereas the response in medial prefrontal cortex and posterior superior temporal sulcus to perceived agency did not change with age. Dynamic causal modeling demonstrated that their effective connectivity remained stable. The pattern of hemodynamic response was not related to regional gray matter volume loss. These findings suggest that the neural response associated with emotional empathy lessened with age, whereas the response to perceived agency is preserved.
Collapse
Affiliation(s)
- Yao-Chu Chen
- Institute of Neuroscience and Brain Research Center, National Yang-Ming University, Taipei, Taiwan
| | - Cheng-Chiang Chen
- Institute of Neuroscience and Brain Research Center, National Yang-Ming University, Taipei, Taiwan; Department of Neurology, Cathay General Hospital, Hsinchu, Taiwan
| | - Jean Decety
- Department of Psychology and Department of Psychiatry and Behavioral Neuroscience, The University of Chicago, Chicago, IL, USA
| | - Yawei Cheng
- Institute of Neuroscience and Brain Research Center, National Yang-Ming University, Taipei, Taiwan; Department of Rehabilitation, National Yang-Ming University Hospital, Yilan, Taiwan.
| |
Collapse
|
44
|
Krainik A, Villien M, Troprès I, Attyé A, Lamalle L, Bouvier J, Pietras J, Grand S, Le Bas JF, Warnking J. Functional imaging of cerebral perfusion. Diagn Interv Imaging 2013; 94:1259-78. [PMID: 24011870 DOI: 10.1016/j.diii.2013.08.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The functional imaging of perfusion enables the study of its properties such as the vasoreactivity to circulating gases, the autoregulation and the neurovascular coupling. Downstream from arterial stenosis, this imaging can estimate the vascular reserve and the risk of ischemia in order to adapt the therapeutic strategy. This method reveals the hemodynamic disorders in patients suffering from Alzheimer's disease or with arteriovenous malformations revealed by epilepsy. Functional MRI of the vasoreactivity also helps to better interpret the functional MRI activation in practice and in clinical research.
Collapse
Affiliation(s)
- A Krainik
- Clinique universitaire de neuroradiologie et IRM, CHU de Grenoble, CS 10217, 38043 Grenoble cedex, France; Inserm U836, université Joseph-Fourier, site santé, chemin Fortuné-Ferrini, 38706 La Tronche cedex, France; UMS IRMaGe, unité IRM 3T recherche, CHU de Grenoble, CS 10217, 38043 Grenoble cedex 9, France.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
45
|
Regional homogeneity of resting-state fMRI contributes to both neurovascular and task activation variations. Magn Reson Imaging 2013; 31:1492-500. [PMID: 23969197 DOI: 10.1016/j.mri.2013.07.005] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Revised: 06/15/2013] [Accepted: 07/13/2013] [Indexed: 11/21/2022]
Abstract
The task induced blood oxygenation level dependent signal changes observed using functional magnetic resonance imaging (fMRI) are critically dependent on the relationship between neuronal activity and hemodynamic response. Therefore, understanding the nature of neurovascular coupling is important when interpreting fMRI signal changes evoked via task. In this study, we used regional homogeneity (ReHo), a measure of local synchronization of the BOLD time series, to investigate whether the similarities of one voxel with the surrounding voxels are a property of neurovascular coupling. FMRI scans were obtained from fourteen subjects during bilateral finger tapping (FTAP), digit-symbol substitution (DSST) and periodic breath holding (BH) paradigm. A resting-state scan was also obtained for each of the subjects for 4min using identical imaging parameters. Inter-voxel correlation analyses were conducted between the resting-state ReHo, resting-state amplitude of low frequency fluctuations (ALFF), BH responses and task activations within the masks related to task activations. There was a reliable mean voxel-wise spatial correlation between ReHo and other neurovascular variables (BH responses and ALFF). We observed a moderate correlation between ReHo and task activations (FTAP: r=0.32; DSST: r=0.22) within the task positive network and a small yet reliable correlation within the default mode network (DSST: r=-0.08). Subsequently, a linear regression was used to estimate the contribution of ReHo, ALFF and BH responses to the task activated voxels. The unique contribution of ReHo was minimal. The results suggest that regional synchrony of the BOLD activity is a property that can explain the variance of neurovascular coupling and task activations; but its contribution to task activations can be accounted for by other neurovascular factors such as the ALFF.
Collapse
|
46
|
Age-related differences in memory-encoding fMRI responses after accounting for decline in vascular reactivity. Neuroimage 2013; 78:415-25. [PMID: 23624491 DOI: 10.1016/j.neuroimage.2013.04.053] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2012] [Revised: 04/02/2013] [Accepted: 04/15/2013] [Indexed: 11/22/2022] Open
Abstract
BOLD fMRI has provided a wealth of information about the aging brain. A common finding is that posterior regions of the brain manifest an age-related decrease in activation while the anterior regions show an age-related increase. Several neurocognitive models have been proposed to interpret these findings. However, one issue that has not been sufficiently considered to date is that the BOLD signal is based on vascular responses secondary to neural activity. Thus the above findings could be in part due to a vascular change, especially in view of the expected decline of vascular health with age. In the present study, we aim to examine age-related differences in memory-encoding fMRI response in the context of vascular aging. One hundred and thirty healthy subjects ranging from 20 to 89 years old underwent a scene-viewing fMRI task and, in the same session, cerebrovascular reactivity (CVR) was measured in each subject using a CO2-inhalation task. Without accounting for the influence of vascular changes, the task-activated fMRI signal showed the typical age-related decrease in visual cortex and medial temporal lobe (MTL), but manifested an increase in the right inferior frontal gyrus (IFG). In the same individuals, an age-related CVR reduction was observed in all of these regions. We then used a previously proposed normalization approach to calculate a CVR-corrected fMRI signal, which was defined as the uncorrected signal divided by CVR. Based on the CVR-corrected fMRI signal, an age-related increase is now seen in both the left and right sides of IFG; and no brain regions showed a signal decrease with age. We additionally used a model-based approach to examine the fMRI data in the context of CVR, which again suggested an age-related change in the two frontal regions, but not in the visual and MTL regions.
Collapse
|
47
|
Tyndall AV, Davenport MH, Wilson BJ, Burek GM, Arsenault-Lapierre G, Haley E, Eskes GA, Friedenreich CM, Hill MD, Hogan DB, Longman RS, Anderson TJ, Leigh R, Smith EE, Poulin MJ. The brain-in-motion study: effect of a 6-month aerobic exercise intervention on cerebrovascular regulation and cognitive function in older adults. BMC Geriatr 2013; 13:21. [PMID: 23448504 PMCID: PMC3598522 DOI: 10.1186/1471-2318-13-21] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Accepted: 02/21/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Aging and physical inactivity are associated with declines in some cognitive domains and cerebrovascular function, as well as an elevated risk of cerebrovascular disease and other morbidities. With the increase in the number of sedentary older Canadians, promoting healthy brain aging is becoming an increasingly important population health issue. Emerging research suggests that higher levels of physical fitness at any age are associated with better cognitive functioning and this may be mediated, at least in part, by improvements in cerebrovascular reserve. We are currently conducting a study to determine: if a structured 6-month aerobic exercise program is associated with improvements or maintenance of both cerebrovascular function and cognitive abilities in older individuals; and, the extent to which any changes seen persist 6 months after the completion of the structured exercise program. METHODS/DESIGN Two hundred and fifty men and women aged 55-80 years are being enrolled into an 18-month combined quasi-experimental and prospective cohort study. Participants are eligible for enrollment into the study if they are inactive (i.e., not participating in regular physical activity), non-smokers, have a body mass index <35.0 kg/m(2), are free of significant cognitive impairment (defined as a Montreal Cognitive Assessment score of 24 or more), and do not have clinically significant cardiovascular, cerebrovascular disease, or chronic obstructive pulmonary airway disease. Repeated measurements are done during three sequential six-month phases: 1) pre-intervention; 2) aerobic exercise intervention; and 3) post-intervention. These outcomes include: cardiorespiratory fitness, resting cerebral blood flow, cerebrovascular reserve, and cognitive function. DISCUSSION This is the first study to our knowledge that will examine contemporaneously the effect of an exercise intervention on both cerebrovascular reserve and cognition in an older population. This study will further our understanding of whether cerebrovascular mechanisms might explain how exercise promotes healthy brain aging. In addition our study will address the potential of increasing physical activity to prevent age-associated cognitive decline.
Collapse
Affiliation(s)
- Amanda V Tyndall
- Department of Physiology & Pharmacology, Faculty of Medicine, University of Calgary, Calgary, Alberta T2N 4N1, Canada
- Hotchkiss Brain Institute, Faculty of Medicine, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Margie H Davenport
- Department of Physiology & Pharmacology, Faculty of Medicine, University of Calgary, Calgary, Alberta T2N 4N1, Canada
- Hotchkiss Brain Institute, Faculty of Medicine, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Ben J Wilson
- Department of Medicine, Faculty of Medicine, University of Calgary, Calgary, Alberta, T2N 4N1, Canada
| | - Grazyna M Burek
- Department of Physiology & Pharmacology, Faculty of Medicine, University of Calgary, Calgary, Alberta T2N 4N1, Canada
- Hotchkiss Brain Institute, Faculty of Medicine, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Genevieve Arsenault-Lapierre
- Department of Physiology & Pharmacology, Faculty of Medicine, University of Calgary, Calgary, Alberta T2N 4N1, Canada
- Hotchkiss Brain Institute, Faculty of Medicine, University of Calgary, Calgary, Alberta T2N 4N1, Canada
- Department of Clinical Neurosciences, Faculty of Medicine, University of Calgary, Calgary, Alberta, T2N 4N1, Canada
| | - Eryka Haley
- Department of Physiology & Pharmacology, Faculty of Medicine, University of Calgary, Calgary, Alberta T2N 4N1, Canada
- Hotchkiss Brain Institute, Faculty of Medicine, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Gail A Eskes
- Department of Physiology & Pharmacology, Faculty of Medicine, University of Calgary, Calgary, Alberta T2N 4N1, Canada
- Department of Psychiatry, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, B3H 2E2, Canada
- Department of Psychology, Faculty of Science, Dalhousie University, Halifax, Nova Scotia, B3H 4R2, Canada
- Department of Medicine (Neurology), Dalhousie University, Halifax, Nova Scotia, B3H 3A7, Canada
| | - Christine M Friedenreich
- Department of Population Health Research, Alberta Health Services-Cancer Care, Calgary, Alberta, T2S 3C3, Canada
- Department of Oncology, Faculty of Medicine, University of Calgary, Calgary, Alberta, T2N 4N1, Canada
- Department of Community Health Sciences, Faculty of Medicine, Faculty of Medicine, University of Calgary, Calgary, Alberta, T2N 4N1, Canada
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, T2N 1N4, Canada
| | - Michael D Hill
- Hotchkiss Brain Institute, Faculty of Medicine, University of Calgary, Calgary, Alberta T2N 4N1, Canada
- Department of Medicine, Faculty of Medicine, University of Calgary, Calgary, Alberta, T2N 4N1, Canada
- Department of Clinical Neurosciences, Faculty of Medicine, University of Calgary, Calgary, Alberta, T2N 4N1, Canada
- Department of Community Health Sciences, Faculty of Medicine, Faculty of Medicine, University of Calgary, Calgary, Alberta, T2N 4N1, Canada
- Department of Radiology, Faculty of Medicine, University of Calgary, Calgary, Alberta, T2N 4N1, Canada
| | - David B Hogan
- Hotchkiss Brain Institute, Faculty of Medicine, University of Calgary, Calgary, Alberta T2N 4N1, Canada
- Department of Medicine, Faculty of Medicine, University of Calgary, Calgary, Alberta, T2N 4N1, Canada
- Department of Clinical Neurosciences, Faculty of Medicine, University of Calgary, Calgary, Alberta, T2N 4N1, Canada
- Department of Community Health Sciences, Faculty of Medicine, Faculty of Medicine, University of Calgary, Calgary, Alberta, T2N 4N1, Canada
- Brenda Stafford Foundation Chair in Geriatric Medicine, Faculty of Medicine, University of Calgary, Calgary, Alberta, T2N 4N1, Canada
| | - R Stewart Longman
- Hotchkiss Brain Institute, Faculty of Medicine, University of Calgary, Calgary, Alberta T2N 4N1, Canada
- Psychology Service, Alberta Health Services, Foothills Hospital, Calgary, Alberta, T2N 2T9, Canada
| | - Todd J Anderson
- University of Calgary, Calgary, Alberta, T2N 4N1, Canada
- Department of Cardiac Science, Faculty of Medicine, University of Calgary, Calgary, Alberta, T2N 4N1, Canada
| | - Richard Leigh
- Department of Physiology & Pharmacology, Faculty of Medicine, University of Calgary, Calgary, Alberta T2N 4N1, Canada
- Department of Medicine, Faculty of Medicine, University of Calgary, Calgary, Alberta, T2N 4N1, Canada
- Airway Inflammation Research Group, Faculty of Medicine, University of Calgary, Calgary, Alberta, T2N 4N1, Canada
- Snyder Institute for Chronic Diseases, Faculty of Medicine, University of Calgary, Calgary, Alberta, T2N 4N1, Canada
| | - Eric E Smith
- Hotchkiss Brain Institute, Faculty of Medicine, University of Calgary, Calgary, Alberta T2N 4N1, Canada
- Department of Clinical Neurosciences, Faculty of Medicine, University of Calgary, Calgary, Alberta, T2N 4N1, Canada
- Department of Community Health Sciences, Faculty of Medicine, Faculty of Medicine, University of Calgary, Calgary, Alberta, T2N 4N1, Canada
- Department of Radiology, Faculty of Medicine, University of Calgary, Calgary, Alberta, T2N 4N1, Canada
| | - Marc J Poulin
- Department of Physiology & Pharmacology, Faculty of Medicine, University of Calgary, Calgary, Alberta T2N 4N1, Canada
- Hotchkiss Brain Institute, Faculty of Medicine, University of Calgary, Calgary, Alberta T2N 4N1, Canada
- Department of Clinical Neurosciences, Faculty of Medicine, University of Calgary, Calgary, Alberta, T2N 4N1, Canada
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, T2N 1N4, Canada
- University of Calgary, Calgary, Alberta, T2N 4N1, Canada
| |
Collapse
|
48
|
Tomassini V, Matthews PM, Thompson AJ, Fuglø D, Geurts JJ, Johansen-Berg H, Jones DK, Rocca MA, Wise RG, Barkhof F, Palace J. Neuroplasticity and functional recovery in multiple sclerosis. Nat Rev Neurol 2012; 8:635-46. [PMID: 22986429 PMCID: PMC3770511 DOI: 10.1038/nrneurol.2012.179] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The development of therapeutic strategies that promote functional recovery is a major goal of multiple sclerosis (MS) research. Neuroscientific and methodological advances have improved our understanding of the brain's recovery from damage, generating novel hypotheses about potential targets and modes of intervention, and laying the foundation for development of scientifically informed recovery-promoting strategies in interventional studies. This Review aims to encourage the transition from characterization of recovery mechanisms to development of strategies that promote recovery in MS. We discuss current evidence for functional reorganization that underlies recovery and its implications for development of new recovery-oriented strategies in MS. Promotion of functional recovery requires an improved understanding of recovery mechanisms that can be modulated by interventions and the development of robust measurements of therapeutic effects. As imaging methods can be used to measure functional and structural alterations associated with recovery, this Review discusses their use to obtain reliable markers of the effects of interventions.
Collapse
|
49
|
Age-related changes in the somatosensory processing of tactile stimulation--an fMRI study. Behav Brain Res 2012; 238:259-64. [PMID: 23123141 DOI: 10.1016/j.bbr.2012.10.038] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Revised: 10/17/2012] [Accepted: 10/20/2012] [Indexed: 11/20/2022]
Abstract
Age-related changes in brain function are complex. Although ageing is associated with a reduction in cerebral blood flow and neuronal activity, task-related processing is often correlated with an enlargement of the corresponding and additionally recruited brain areas. This supplemental employment is considered an attempt to compensate for deficits in the ageing brain. Although there are contradictory reports regarding the role of the primary somatosensory cortex (SI), currently, there is little knowledge about age-related functional changes in other brain areas in the somatosensory network (secondary somatosensory cortex (SII), and insular, anterior (ACC) and posterior cingulate cortices (PCC)). We investigated 16 elderly (age range, 62-71 years) and 18 young subjects (age range, 21-28 years) by determining the current perception threshold (CPT) and applying functional magnetic resonance imaging (fMRI) using a 3.0 Tesla scanner under tactile stimulation of the right hand. CPT was positively correlated with age. fMRI analysis revealed significantly increased activation in the contralateral SI and ipsilateral motor cortex in elderly subjects. Furthermore, we demonstrated age-related reductions in the activity in the SII, ACC, PCC, and dorsal parts of the corpus callosum. Our study revealed dramatic age-related differences in the processing of a simple tactile stimulus in the somatosensory network. Specifically, we detected enhanced activation in the contralateral SI and ipsilateral motor cortex assumingly caused by deficient inhibition and decreased activation in later stages of somatosensory processing (SII, cingulate cortex) in elderly subjects. These results indicate that, in addition to over-activation to compensate for impaired brain functions, there are complex mechanisms of modified inhibition and excitability involved in somatosensory processing in the ageing brain.
Collapse
|
50
|
Kallenberg K, Rühlmann J, Baudewig J, Larsen J, Gröschel S, Dechent P, Kastrup A, Knauth M. Analysis of reserve capacity and subsequent stenting in a case of subacute occlusion of the internal carotid artery. Clin Neuroradiol 2012; 23:225-9. [PMID: 22960936 PMCID: PMC3739872 DOI: 10.1007/s00062-012-0172-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Accepted: 08/13/2012] [Indexed: 11/20/2022]
Abstract
Introduction While acute internal carotid artery (ICA) occlusions are increasingly being treated with carotid angioplasty and stenting (CAS), the utility of CAS in subacute stages is unclear. Case Report A 65-year-old patient with an acute left ICA occlusion and pre-existing occlusion on the right side presented with dysarthria and central right-sided facial palsy. Carbon dioxide (CO2) reactivity within the left hemisphere was markedly reduced. Due to acute deterioration despite maximal conservative therapy CAS was performed 8 days after the initial event with an excellent result and symptoms subsided. Conclusion CAS in subacute ICA occlusion is possible. Patients should be selected carefully. Assessment of cerebrovascular CO2 reactivity might provide valuable information.
Collapse
|