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Physical activity, motor performance and skill learning: a focus on primary motor cortex in healthy aging. Exp Brain Res 2021; 239:3431-3438. [PMID: 34499187 DOI: 10.1007/s00221-021-06218-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 09/02/2021] [Indexed: 01/03/2023]
Abstract
Participation in physical activity benefits brain health and function. Cognitive function generally demonstrates a noticeable effect of physical activity, but much less is known about areas responsible for controlling movement, such as primary motor cortex (M1). While more physical activity may support M1 plasticity in older adults, the neural mechanisms underlying this beneficial effect remain poorly understood. Aging is inevitably accompanied by diminished motor performance, and the extent of plasticity may also be less in older adults compared with young. Motor complications with aging may, perhaps unsurprisingly, contribute to reduced physical activity in older adults. While the development of non-invasive brain stimulation techniques have identified that human M1 is a crucial site for learning motor skills and recovery of motor function after injury, a considerable lack of knowledge remains about how physical activity impacts M1 with healthy aging. Reducing impaired neural activity in older adults may have important implications after neurological insult, such as stroke, which is more common with advancing age. Therefore, a better understanding about the effects of physical activity on M1 processes and motor learning in older adults may promote healthy aging, but also allow us to facilitate recovery of motor function after neurological injury. This article will initially provide a brief overview of the neurophysiology of M1 in the context of learning motor skills, with a focus on healthy aging in humans. This information will then be proceeded by a more detailed assessment that focuses on whether physical activity benefits motor function and human M1 processes.
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Cassady KE, Adams JN, Chen X, Maass A, Harrison TM, Landau S, Baker S, Jagust W. Alzheimer's Pathology Is Associated with Dedifferentiation of Intrinsic Functional Memory Networks in Aging. Cereb Cortex 2021; 31:4781-4793. [PMID: 34037210 PMCID: PMC8408467 DOI: 10.1093/cercor/bhab122] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 04/13/2021] [Accepted: 04/14/2021] [Indexed: 11/14/2022] Open
Abstract
In presymptomatic Alzheimer's disease (AD), beta-amyloid plaques (Aβ) and tau tangles accumulate in distinct spatiotemporal patterns within the brain, tracking closely with episodic memory decline. Here, we tested whether age-related changes in the segregation of the brain's intrinsic functional episodic memory networks-anterior-temporal (AT) and posterior-medial (PM) networks-are associated with the accumulation of Aβ, tau, and memory decline using fMRI and PET. We found that AT and PM networks were less segregated in older than that in younger adults and this reduced specialization was associated with more tau and Aβ in the same regions. The effect of network dedifferentiation on memory depended on the amount of Aβ and tau, with low segregation and pathology associated with better performance at baseline and low segregation and high pathology related to worse performance over time. This pattern suggests a compensation phase followed by a degenerative phase in the early, preclinical phase of AD.
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Affiliation(s)
- Kaitlin E Cassady
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Helen Wills Neuroscience Institute, University of California Berkeley, Berkeley, CA 94720, USA
| | - Jenna N Adams
- Helen Wills Neuroscience Institute, University of California Berkeley, Berkeley, CA 94720, USA
| | - Xi Chen
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Helen Wills Neuroscience Institute, University of California Berkeley, Berkeley, CA 94720, USA
| | - Anne Maass
- German Center for Neurodegenerative Disease, Magdeburg 39120, Germany
| | - Theresa M Harrison
- Helen Wills Neuroscience Institute, University of California Berkeley, Berkeley, CA 94720, USA
| | - Susan Landau
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Helen Wills Neuroscience Institute, University of California Berkeley, Berkeley, CA 94720, USA
| | - Suzanne Baker
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - William Jagust
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Helen Wills Neuroscience Institute, University of California Berkeley, Berkeley, CA 94720, USA
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Hausman HK, Jackson TB, Goen JRM, Bernard JA. From Synchrony to Asynchrony: Cerebellar-Basal Ganglia Functional Circuits in Young and Older Adults. Cereb Cortex 2021; 30:718-729. [PMID: 31219563 DOI: 10.1093/cercor/bhz121] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 05/14/2019] [Accepted: 05/15/2019] [Indexed: 01/28/2023] Open
Abstract
Resting state functional magnetic resonance imaging (rs-fMRI) has indicated disruptions in functional connectivity in older adults (OA) relative to young adults (YA). While age differences in cortical networks are well studied, differences in subcortical networks are poorly understood. Both the cerebellum and the basal ganglia are of particular interest given their role in cognitive and motor functions, and work in nonhuman primates has demonstrated direct reciprocal connections between these regions. Here, our goal was twofold. First, we were interested in delineating connectivity patterns between distinct regions of the cerebellum and basal ganglia, known to have topologically distinct connectivity patterns with cortex. Our second goal was to quantify age differences in these cerebellar-striatal circuits. We performed a targeted rs-fMRI analysis of the cerebellum and basal ganglia in 33 YA and 31 OA individuals. In the YA, we found significant connectivity both within and between the cerebellum and basal ganglia, in patterns supporting semi-discrete circuits that may differentially subserve motor and cognitive performance. We found a shift in connectivity, from one of synchrony in YA, to asynchrony in OA, resulting in substantial age differences. Connectivity was also associated with behavior. These findings significantly advance our understanding of cerebellar-basal ganglia interactions in the human brain.
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Affiliation(s)
- Hanna K Hausman
- Department of Psychological and Brain Sciences, Texas A&M University, College Station, USA
| | - T Bryan Jackson
- Department of Psychological and Brain Sciences, Texas A&M University, College Station, USA
| | - James R M Goen
- Department of Psychological and Brain Sciences, Texas A&M University, College Station, USA
| | - Jessica A Bernard
- Department of Psychological and Brain Sciences, Texas A&M University, College Station, USA.,Texas A&M Institute for Neuroscience, Texas A&M University, College Station, USA
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Mueller SG, Muller AM. Brainstem Dysfunction in Healthy Aging. Neuroimage 2021; 238:118241. [PMID: 34116149 DOI: 10.1016/j.neuroimage.2021.118241] [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: 02/02/2021] [Revised: 04/29/2021] [Accepted: 06/04/2021] [Indexed: 11/16/2022] Open
Abstract
The brainstem controls sub-cortical and cortical activity and influences the processing of incoming information. The goal of this study was to characterize age related alterations of brainstem-brain interactions during different brain states detected by dynamic analysis of task-free fMRI. 79 young (20-40 years) and 51 older adults (55-80 years) were studied. Internal brainstem structures were segmented using a new multi-contrast segmentation approach. Brain and brainstem gray matter segmentations were warped onto a population template. The ICV-corrected Jacobian determinants were converted into z-score maps and the means from 420 cortical/subcortical/brainstem rois extracted. The fMRI was preprocessed in SPM12/Conn18 and the BOLD signal from 420 cortical/subcortical/brainstem rois extracted. A dynamic task-free analysis approach based on hierarchical cluster analysis was used to identify 15 brain states that were characterized using graph analysis (strength, diversity, modularity). Kruskal-Wallis tests and Spearman correlations were used for statistical analysis. One brain state (cluster 21) occurred more often in older adults (p=0.008). It was characterized by a lower mean modular strength and brainstem-cortical strength in older adults compared to younger adults. Global age related gray matter differences were positively correlated with brain state 21's modular strength. Furthermore, brain state 21 duration was negatively correlated with working memory (r = -0.28, p=0.002). The findings suggest an age related weakening of the within and between network synchronization at the brainstem level during brain state 21 in older adults that negatively affects cortical and subcortical synchronization and working memory performance.
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Affiliation(s)
- S G Mueller
- Dept. of Radiology, University of California, San Francisco, CA.
| | - A M Muller
- Dept. of Radiology, University of California, San Francisco, CA.
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Fettrow T, Hupfeld K, Tays G, Clark DJ, Reuter-Lorenz PA, Seidler RD. Brain activity during walking in older adults: Implications for compensatory versus dysfunctional accounts. Neurobiol Aging 2021; 105:349-364. [PMID: 34182403 DOI: 10.1016/j.neurobiolaging.2021.05.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Revised: 05/19/2021] [Accepted: 05/23/2021] [Indexed: 11/25/2022]
Abstract
A prominent trend in the functional brain imaging literature is that older adults exhibit increased brain activity compared to young adults to perform a given task. This phenomenon has been extensively studied for cognitive tasks, with the field converging on interpretations described in two alternative accounts. One account interprets over-activation in older adults as reflecting neural dysfunction (increased brain activity - indicates poorer performance), whereas another interprets it as neural compensation (increased brain activity - supports better performance). Here we review studies that have recorded brain activity and walking measurements in older adults, and we categorize their findings as reflecting either neural dysfunction or neural compensation. Based on this synthesis, we recommend including multiple task difficulty levels in future work to help differentiate if and when compensation fails as the locomotion task becomes more difficult. Using multiple task difficulty levels with neuroimaging will lead to a more advanced understanding of how age-related changes in locomotor brain activity fit with existing accounts of brain aging and support the development of targeted neural rehabilitation techniques.
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Affiliation(s)
- Tyler Fettrow
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA.
| | - Kathleen Hupfeld
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Grant Tays
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - David J Clark
- Department of Aging and Geriatric Research, University of Florida, Gainesville, FL, USA; Brain Rehabilitation Research Center, Malcom Randall VA Medical Center, Gainesville, FL, USA
| | | | - Rachael D Seidler
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA; Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL, USA
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Rideaux R. No balance between glutamate+glutamine and GABA+ in visual or motor cortices of the human brain: A magnetic resonance spectroscopy study. Neuroimage 2021; 237:118191. [PMID: 34023450 DOI: 10.1016/j.neuroimage.2021.118191] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 04/27/2021] [Accepted: 05/19/2021] [Indexed: 12/28/2022] Open
Abstract
Theoretical work, supported by electrophysiological evidence, asserts that a balance between excitation and inhibition (E/I) is critical for healthy brain function. In magnetic resonance spectroscopy (MRS) studies, the ratio of excitatory (glutamate) and inhibitory (γ-aminobutyric acid, GABA) neurotransmitters is often used as a proxy for this E/I balance. Recent MRS work found a positive correlation between GABA+ and Glx (glutamate+glutamine) in medial parietal cortex, providing validation for this proxy and supporting the link between the E/I balance observed in electrophysiology and that detected with MRS. Here we assess the same relationship, between GABA+ and Glx, in visual and motor cortices of male and female human participants. We find moderate to strong evidence that there is no positive correlation between these neurotransmitters in either location. We show this holds true when controlling for a range of other factors (i.e., demographics, signal quality, tissue composition, other neurochemicals) and regardless of the state of neural activity (i.e., resting/active). These results show that there is no brain-wide balance between excitatory and inhibitory neurotransmitters and indicates a dissociation between the E/I balance observed in electrophysiological work and the ratio of MRS-detected neurotransmitters.
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Affiliation(s)
- Reuben Rideaux
- Department of Psychology, Downing Street, University of Cambridge, UK; Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia.
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Iordan AD, Moored KD, Katz B, Cooke KA, Buschkuehl M, Jaeggi SM, Polk TA, Peltier SJ, Jonides J, Reuter‐Lorenz PA. Age differences in functional network reconfiguration with working memory training. Hum Brain Mapp 2021; 42:1888-1909. [PMID: 33534925 PMCID: PMC7978135 DOI: 10.1002/hbm.25337] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 12/21/2020] [Accepted: 12/22/2020] [Indexed: 12/16/2022] Open
Abstract
Demanding cognitive functions like working memory (WM) depend on functional brain networks being able to communicate efficiently while also maintaining some degree of modularity. Evidence suggests that aging can disrupt this balance between integration and modularity. In this study, we examined how cognitive training affects the integration and modularity of functional networks in older and younger adults. Twenty three younger and 23 older adults participated in 10 days of verbal WM training, leading to performance gains in both age groups. Older adults exhibited lower modularity overall and a greater decrement when switching from rest to task, compared to younger adults. Interestingly, younger but not older adults showed increased task-related modularity with training. Furthermore, whereas training increased efficiency within, and decreased participation of, the default-mode network for younger adults, it enhanced efficiency within a task-specific salience/sensorimotor network for older adults. Finally, training increased segregation of the default-mode from frontoparietal/salience and visual networks in younger adults, while it diffusely increased between-network connectivity in older adults. Thus, while younger adults increase network segregation with training, suggesting more automated processing, older adults persist in, and potentially amplify, a more integrated and costly global workspace, suggesting different age-related trajectories in functional network reorganization with WM training.
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Affiliation(s)
| | - Kyle D. Moored
- Department of Mental Health, Bloomberg School of Public HealthJohns Hopkins UniversityBaltimoreMarylandUSA
| | - Benjamin Katz
- Department of Human Development and Family ScienceVirginia TechBlacksburgVirginiaUSA
| | | | | | - Susanne M. Jaeggi
- School of EducationUniversity of California‐IrvineIrvineCaliforniaUSA
| | - Thad A. Polk
- Department of PsychologyUniversity of MichiganAnn ArborMichiganUSA
| | - Scott J. Peltier
- Functional MRI LaboratoryUniversity of MichiganAnn ArborMichiganUSA
- Department of Biomedical EngineeringUniversity of MichiganAnn ArborMichiganUSA
| | - John Jonides
- Department of PsychologyUniversity of MichiganAnn ArborMichiganUSA
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Tracking Age Differences in Neural Distinctiveness across Representational Levels. J Neurosci 2021; 41:3499-3511. [PMID: 33637559 DOI: 10.1523/jneurosci.2038-20.2021] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 01/12/2021] [Accepted: 02/10/2021] [Indexed: 11/21/2022] Open
Abstract
The distinctiveness of neural information representation is crucial for successful memory performance but declines with advancing age. Computational models implicate age-related neural dedifferentiation on the level of item representations, but previous studies mostly focused on age differences of categorical information representation in higher-order visual regions. In an age-comparative fMRI study, we combined univariate analyses and whole-brain searchlight pattern similarity analyses to elucidate age differences in neural distinctiveness at both category and item levels and their relation to memory. Thirty-five younger (18-27 years old) and 32 older (67-75 years old) women and men incidentally encoded images of faces and houses, followed by an old/new recognition memory task. During encoding, age-related neural dedifferentiation was shown as reduced category-selective processing in ventral visual cortex and impoverished item specificity in occipital regions. Importantly, successful subsequent memory performance built on high item stability, that is, high representational similarity between initial and repeated presentation of an item, which was greater in younger than older adults. Overall, we found that differences in representational distinctiveness coexist across representational levels and contribute to interindividual and intraindividual variability in memory success, with item specificity being the strongest contributor. Our results close an important gap in the literature, showing that older adults' neural representation of item-specific information in addition to categorical information is reduced compared with younger adults.SIGNIFICANCE STATEMENT A long-standing hypothesis links age-related cognitive decline to a loss of neural specificity. While previous evidence supports the notion of age-related neural dedifferentiation of category-level information in ventral visual cortex, whether or not age differences exist at the item level was a matter of debate. Here, we observed age group differences at both levels as well as associations between both categorical distinctiveness and item specificity to memory performance, with item specificity being the strongest contributor. Importantly, age differences in occipital item specificity were largely due to reduced item stability across repetitions in older adults. Our results suggest that age differences in neural representations can be observed across the entire cortical hierarchy and are not limited to category-level information.
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Contribution of muscle proprioception to limb movement perception and proprioceptive decline with ageing. CURRENT OPINION IN PHYSIOLOGY 2021. [DOI: 10.1016/j.cophys.2021.01.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Sasaki R, Otsuru N, Miyaguchi S, Kojima S, Watanabe H, Ohno K, Sakurai N, Kodama N, Sato D, Onishi H. Influence of Brain-Derived Neurotrophic Factor Genotype on Short-Latency Afferent Inhibition and Motor Cortex Metabolites. Brain Sci 2021; 11:brainsci11030395. [PMID: 33804682 PMCID: PMC8003639 DOI: 10.3390/brainsci11030395] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 03/01/2021] [Accepted: 03/18/2021] [Indexed: 12/11/2022] Open
Abstract
The Met allele of the brain-derived neurotrophic factor (BDNF) gene confers reduced cortical BDNF expression and associated neurobehavioral changes. BDNF signaling influences the survival, development, and synaptic function of cortical networks. Here, we compared gamma-aminobutyric acid (GABA)ergic network activity in the human primary motor cortex (M1) between the Met (Val/Met and Met/Met) and non-Met (Val/Val) genotype groups. Short- and long-interval intracortical inhibition, short-latency afferent inhibition (SAI), and long-latency afferent inhibition were measured using transcranial magnetic stimulation (TMS) as indices of GABAergic activity. Furthermore, the considerable inter-individual variability in inhibitory network activity typically measured by TMS may be affected not only by GABA but also by other pathways, including glutamatergic and cholinergic activities; therefore, we used 3-T magnetic resonance spectroscopy (MRS) to measure the dynamics of glutamate plus glutamine (Glx) and choline concentrations in the left M1, left somatosensory cortex, and right cerebellum. All inhibitory TMS conditions produced significantly smaller motor-evoked potentials than single-pulses. SAI was significantly stronger in the Met group than in the Val/Val group. Only the M1 Glx concentration was significantly lower in the Met group, while the BDNF genotype did not affect choline concentration in any region. Further, a positive correlation was observed between SAI and Glx concentrations only in M1. Our findings provide evidence that the BDNF genotype regulates both the inhibitory and excitatory circuits in human M1. In addition, lower Glx concentration in the M1 of Met carriers may alter specific inhibitory network on M1, thereby influencing the cortical signal processing required for neurobehavioral functions.
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Affiliation(s)
- Ryoki Sasaki
- Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare, Niigata City, Niigata 950-3198, Japan; (N.O.); (S.M.); (S.K.); (H.W.); (N.K.); (D.S.); (H.O.)
- Discipline of Physiology, Adelaide Medical School, The University of Adelaide, Adelaide 5000, Australia
- Correspondence: ; Tel.: +81-25-257-4445
| | - Naofumi Otsuru
- Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare, Niigata City, Niigata 950-3198, Japan; (N.O.); (S.M.); (S.K.); (H.W.); (N.K.); (D.S.); (H.O.)
- Department of Physical Therapy, Niigata University of Health and Welfare, Niigata City, Niigata 950-3198, Japan
| | - Shota Miyaguchi
- Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare, Niigata City, Niigata 950-3198, Japan; (N.O.); (S.M.); (S.K.); (H.W.); (N.K.); (D.S.); (H.O.)
- Department of Physical Therapy, Niigata University of Health and Welfare, Niigata City, Niigata 950-3198, Japan
| | - Sho Kojima
- Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare, Niigata City, Niigata 950-3198, Japan; (N.O.); (S.M.); (S.K.); (H.W.); (N.K.); (D.S.); (H.O.)
- Department of Physical Therapy, Niigata University of Health and Welfare, Niigata City, Niigata 950-3198, Japan
| | - Hiraku Watanabe
- Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare, Niigata City, Niigata 950-3198, Japan; (N.O.); (S.M.); (S.K.); (H.W.); (N.K.); (D.S.); (H.O.)
| | - Ken Ohno
- Department of Radiological Technology, Niigata University of Health and Welfare, Niigata City, Niigata 950-3198, Japan; (K.O.); (N.S.)
| | - Noriko Sakurai
- Department of Radiological Technology, Niigata University of Health and Welfare, Niigata City, Niigata 950-3198, Japan; (K.O.); (N.S.)
| | - Naoki Kodama
- Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare, Niigata City, Niigata 950-3198, Japan; (N.O.); (S.M.); (S.K.); (H.W.); (N.K.); (D.S.); (H.O.)
- Department of Radiological Technology, Niigata University of Health and Welfare, Niigata City, Niigata 950-3198, Japan; (K.O.); (N.S.)
| | - Daisuke Sato
- Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare, Niigata City, Niigata 950-3198, Japan; (N.O.); (S.M.); (S.K.); (H.W.); (N.K.); (D.S.); (H.O.)
- Department of Health and Sports, Niigata University of Health and Welfare, Niigata City, Niigata 950-3198, Japan
| | - Hideaki Onishi
- Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare, Niigata City, Niigata 950-3198, Japan; (N.O.); (S.M.); (S.K.); (H.W.); (N.K.); (D.S.); (H.O.)
- Department of Physical Therapy, Niigata University of Health and Welfare, Niigata City, Niigata 950-3198, Japan
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Non-invasive brain stimulation to assess neurophysiologic underpinnings of lower limb motor impairment in multiple sclerosis. J Neurosci Methods 2021; 356:109143. [PMID: 33757762 DOI: 10.1016/j.jneumeth.2021.109143] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 02/20/2021] [Accepted: 03/10/2021] [Indexed: 12/31/2022]
Abstract
BACKGROUND Multiple sclerosis (MS) is a neuroinflammatory disease resulting in axonal demyelination and an amalgamation of symptoms which commonly result in decreased quality of life due to mobility dysfunction and limited participation in meaningful activities. NEW METHOD The use of non-invasive brain stimulation (NIBS) techniques, specifically transcranial magnetic and transcranial direct current stimulation, have been essential in understanding the pathophysiological decrements related to disease progression, particularly with regard to motor impairments. Although the research in this area has primarily focused on the upper extremities, new interest has arisen in understanding the neurophysiological underpinnings of lower limb impairment. Therefore, the purpose of this review is to: first, provide an overview of common NIBS techniques used to explore sensorimotor neurophysiology; second, summarize lower limb neuromuscular and mobility impairments typically observed in PwMS; third, review the current knowledge regarding interactions between TMS-assessed neurophysiology and lower limb impairments in PwMS; and fourth, provide recommendations for future NIBS studies based on current gaps in the literature. RESULTS PwMS exhibit reduced excitability and increased inhibitory neurophysiologic function which has been related to disease severity and lower limb motor impairments. Comparison with existing methods: Moreover, promising results indicate that the use of repetitive stimulation and transcranial direct current stimulation may prime neural adaptability and prove useful as a therapeutic tool in ameliorating lower limb impairments. CONCLUSIONS While these studies are both informative and promising, additional studies are necessary to be conclusive. As such, studies assessing objective measures of lower limb impairments associated with neurophysiological adaptations need further evaluation.
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GABA levels in ventral visual cortex decline with age and are associated with neural distinctiveness. Neurobiol Aging 2021; 102:170-177. [PMID: 33770531 DOI: 10.1016/j.neurobiolaging.2021.02.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 02/15/2021] [Accepted: 02/18/2021] [Indexed: 01/24/2023]
Abstract
Age-related neural dedifferentiation-a decline in the distinctiveness of neural representations in the aging brain-has been associated with age-related declines in cognitive abilities. But why does neural distinctiveness decline with age? Based on prior work in nonhuman primates and more recent work in humans, we hypothesized that the inhibitory neurotransmitter gamma-aminobutyric acid (GABA) declines with age and is associated with neural dedifferentiation in older adults. To test this hypothesis, we used magnetic resonance spectroscopy (MRS) to measure GABA and functional MRI (fMRI) to measure neural distinctiveness in the ventral visual cortex in a set of older and younger participants. Relative to younger adults, older adults exhibited lower GABA levels and less distinct activation patterns for faces and houses in the ventral visual cortex. Furthermore, individual differences in GABA within older adults positively predicted individual differences in neural distinctiveness. These results provide novel support for the view that age-related reductions of GABA contribute to age-related reductions in neural distinctiveness (i.e., neural dedifferentiation) in the human ventral visual cortex.
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63
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Maes C, Cuypers K, Heise KF, Edden RAE, Gooijers J, Swinnen SP. GABA levels are differentially associated with bimanual motor performance in older as compared to young adults. Neuroimage 2021; 231:117871. [PMID: 33607278 PMCID: PMC8275071 DOI: 10.1016/j.neuroimage.2021.117871] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 02/11/2021] [Indexed: 01/23/2023] Open
Abstract
Although gamma aminobutyric acid (GABA) is of particular importance for efficient motor functioning, very little is known about the relationship between regional GABA levels and motor performance. Some studies suggest this relation to be subject to age-related differences even though literature is scarce. To clarify this matter, we employed a comprehensive approach and investigated GABA levels within young and older adults across multiple motor tasks as well as multiple brain regions. Specifically, 30 young and 30 older adults completed a task battery of three different bimanual tasks. Furthermore, GABA levels were obtained within bilateral primary sensorimotor cortex (SM1), bilateral dorsal premotor cortex, the supplementary motor area and bilateral dorsolateral prefrontal cortex (DLPFC) using magnetic resonance spectroscopy. Results indicated that older adults, as compared to their younger counterparts, performed worse on all bimanual tasks and exhibited lower GABA levels in bilateral SM1 only. Moreover, GABA levels across the motor network and DLPFC were differentially associated with performance in young as opposed to older adults on a manual dexterity and bimanual coordination task but not a finger tapping task. Specifically, whereas higher GABA levels related to better manual dexterity within older adults, higher GABA levels predicted poorer bimanual coordination performance in young adults. By determining a task-specific and age-dependent association between GABA levels across the cortical motor network and performance on distinct bimanual tasks, the current study advances insights in the role of GABA for motor performance in the context of aging.
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Affiliation(s)
- Celine Maes
- Movement Control & Neuroplasticity Research Group, Department of Movement Sciences, Group Biomedical Sciences, KU Leuven, Leuven, Belgium; KU Leuven Brain Institute (LBI), Tervuursevest 101 box, Leuven 1501 3001, Belgium.
| | - Koen Cuypers
- Movement Control & Neuroplasticity Research Group, Department of Movement Sciences, Group Biomedical Sciences, KU Leuven, Leuven, Belgium; KU Leuven Brain Institute (LBI), Tervuursevest 101 box, Leuven 1501 3001, Belgium; REVAL Research Institute, Hasselt University, Diepenbeek, Belgium.
| | - Kirstin-Friederike Heise
- Movement Control & Neuroplasticity Research Group, Department of Movement Sciences, Group Biomedical Sciences, KU Leuven, Leuven, Belgium; KU Leuven Brain Institute (LBI), Tervuursevest 101 box, Leuven 1501 3001, Belgium.
| | - Richard A E Edden
- Russel H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, United States
| | - Jolien Gooijers
- Movement Control & Neuroplasticity Research Group, Department of Movement Sciences, Group Biomedical Sciences, KU Leuven, Leuven, Belgium; KU Leuven Brain Institute (LBI), Tervuursevest 101 box, Leuven 1501 3001, Belgium.
| | - Stephan P Swinnen
- Movement Control & Neuroplasticity Research Group, Department of Movement Sciences, Group Biomedical Sciences, KU Leuven, Leuven, Belgium; KU Leuven Brain Institute (LBI), Tervuursevest 101 box, Leuven 1501 3001, Belgium.
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64
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Do TTN, Jung TP, Lin CT. Retrosplenial Segregation Reflects the Navigation Load During Ambulatory Movement. IEEE Trans Neural Syst Rehabil Eng 2021; 29:488-496. [PMID: 33544675 DOI: 10.1109/tnsre.2021.3057384] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Spatial navigation is a complex cognitive process based on vestibular, proprioceptive, and visualcues that are integrated and processed by an extensive network of brain areas. The retrosplenial complex (RSC) is an integral part of coordination and translation between spatial reference frames. Previous studies have demonstrated that the RSC is active during a spatial navigation tasks. The specifics of RSC activity under various navigation loads, however, are still not characterized. This study investigated the local information processed by the RSC under various navigation load conditions manipulated by the number of turns in the physical navigation setup. The results showed that the local information processed via the RSC, which was reflected by the segregation network, was higher when the number of turns increased, suggesting that RSC activity is associated with the navigation task load. The present findings shed light on how the brain processes spatial information in a physical navigation task.
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65
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Levin O, Netz Y, Ziv G. Behavioral and Neurophysiological Aspects of Inhibition-The Effects of Acute Cardiovascular Exercise. J Clin Med 2021; 10:E282. [PMID: 33466667 PMCID: PMC7828827 DOI: 10.3390/jcm10020282] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 01/08/2021] [Accepted: 01/08/2021] [Indexed: 12/28/2022] Open
Abstract
This review summarizes behavioral and neurophysiological aspects of inhibitory control affected by a single bout of cardiovascular exercise. The review also examines the effect of a single bout of cardiovascular exercise on these processes in young adults with a focus on the functioning of prefrontal pathways (including the left dorsolateral prefrontal cortex (DLPFC) and elements of the prefrontal-basal ganglia pathways). Finally, the review offers an overview on the potential effects of cardiovascular exercise on GABA-ergic and glutamatergic neurotransmission in the adult brain and propose mechanisms or processes that may mediate these effects. The main findings show that a single bout of cardiovascular exercise can enhance inhibitory control. In addition, acute exercise appears to facilitate activation of prefrontal brain regions that regulate excitatory and inhibitory pathways (specifically but not exclusively the prefrontal-basal-ganglia pathways) which appear to be impaired in older age. Based on the reviewed studies, we suggest that future work examine the beneficial effects of exercise on the inhibitory networks in the aging brain.
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Affiliation(s)
- Oron Levin
- Movement Control and Neuroplasticity Research Group, Department of Kinesiology, KU Leuven, 3001 Heverlee, Belgium;
- Department of Health Promotion and Rehabilitation, Lithuanian Sports University, LT-44221 Kaunas, Lithuania
| | - Yael Netz
- The Academic College at Wingate, Netanya 4290200, Israel;
| | - Gal Ziv
- The Academic College at Wingate, Netanya 4290200, Israel;
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66
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Noohi F, Kinnaird C, De Dios Y, Kofman IS, Wood SJ, Bloomberg J, Mulavara A, Sienko KH, Polk TA, Seidler RD. Age Differences in Vestibular Brain Connectivity Are Associated With Balance Performance. Front Aging Neurosci 2020; 12:566331. [PMID: 33312123 PMCID: PMC7703342 DOI: 10.3389/fnagi.2020.566331] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 10/27/2020] [Indexed: 11/26/2022] Open
Abstract
Visual and auditory brain network connectivity decline with age, but less is known about age effects on vestibular functional connectivity and its association with behavior. We assessed age differences in the connectivity of the vestibular cortex with other sensory brain regions, both during rest and during vestibular stimulation. We then assessed the relationship between vestibular connectivity and postural stability. A sample of seventeen young and fifteen older adults participated in our study. We assessed the amount of body sway in performing the Romberg balance task, with degraded somatosensory and visual inputs. The results showed no significant difference in balance performance between age groups. However, functional connectivity analyses revealed a main effect of age and condition, suggesting that vestibular connectivity was higher in young adults than older adults, and vestibular connectivity increased from resting state to stimulation trials. Surprisingly, young adults who exhibited higher connectivity during stimulation also had greater body sway. This suggests that young adults who exhibit better balance are those who respond more selectively to vestibular inputs. This correlation is non-significant in older adults, suggesting that the relationship between vestibular functional connectivity and postural stability differs with age.
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Affiliation(s)
- Fatemeh Noohi
- Department of Kinesiology, University of Michigan, Ann Arbor, MI, United States.,Department of Psychology, University of Michigan, Ann Arbor, MI, United States
| | - Catherine Kinnaird
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States
| | | | | | - Scott J Wood
- NASA Johnson Space Center, Houston, TX, United States
| | | | | | - Kathleen H Sienko
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States
| | - Thad A Polk
- Department of Psychology, University of Michigan, Ann Arbor, MI, United States
| | - Rachael D Seidler
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, United States
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67
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Gao M, Wong CHY, Huang H, Shao R, Huang R, Chan CCH, Lee TMC. Connectome-based models can predict processing speed in older adults. Neuroimage 2020; 223:117290. [PMID: 32871259 DOI: 10.1016/j.neuroimage.2020.117290] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/10/2020] [Accepted: 08/17/2020] [Indexed: 12/12/2022] Open
Abstract
Decrement in processing speed (PS) is a primary cognitive morbidity in clinical populations and could significantly influence other cognitive functions, such as attention and memory. Verifying the usefulness of connectome-based models for predicting neurocognitive abilities has significant translational implications on clinical and aging research. In this study, we verified that resting-state functional connectivity could be used to predict PS in 99 older adults by using connectome-based predictive modeling (CPM). We identified two distinct connectome patterns across the whole brain: the fast-PS and slow-PS networks. Relative to the slow-PS network, the fast-PS network showed more within-network connectivity in the motor and visual networks and less between-network connectivity in the motor-visual, motor-subcortical/cerebellum and motor-frontoparietal networks. We further verified that the connectivity patterns for prediction of PS were also useful for predicting attention and memory in the same sample. To test the generalizability and specificity of the connectome-based predictive models, we applied these two connectome models to an independent sample of three age groups (101 younger adults, 103 middle-aged adults and 91 older adults) and confirmed these models could specifically be generalized to predict PS of the older adults, but not the younger and middle-aged adults. Taking all the findings together, the identified connectome-based predictive models are strong for predicting PS in older adults. The application of CPM to predict neurocognitive abilities can complement conventional neurocognitive assessments, bring significant clinical benefits to patient management and aid the clinical diagnoses, prognoses and management of people undergoing the aging process.
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Affiliation(s)
- Mengxia Gao
- The State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong, China; Laboratory of Neuropsychology, The University of Hong Kong, Hong Kong, China
| | - Clive H Y Wong
- The State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong, China; Laboratory of Neuropsychology, The University of Hong Kong, Hong Kong, China
| | - Huiyuan Huang
- School of Psychology, Center for the Study of Applied Psychology, Key Laboratory of Mental Health and Cognitive Science of Guangdong Province, South China Normal University, Guangzhou 510631, China; Key Laboratory of Brain Cognition and Education Sciences (South China Normal University) Ministry of Education
| | - Robin Shao
- The State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong, China; Laboratory of Neuropsychology, The University of Hong Kong, Hong Kong, China
| | - Ruiwang Huang
- School of Psychology, Center for the Study of Applied Psychology, Key Laboratory of Mental Health and Cognitive Science of Guangdong Province, South China Normal University, Guangzhou 510631, China; Key Laboratory of Brain Cognition and Education Sciences (South China Normal University) Ministry of Education.
| | - Chetwyn C H Chan
- Applied Cognitive Neuroscience Laboratory, Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hum Hom, Hong Kong.
| | - Tatia M C Lee
- The State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong, China; Laboratory of Neuropsychology, The University of Hong Kong, Hong Kong, China; Guangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired Intelligence, Guangzhou, China; Laboratory of Emotion and Cognition, The Affiliated Hospital of Guangzhou Medical University, China.
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68
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Age-related GABAergic differences in the primary sensorimotor cortex: A multimodal approach combining PET, MRS and TMS. Neuroimage 2020; 226:117536. [PMID: 33186716 PMCID: PMC7894275 DOI: 10.1016/j.neuroimage.2020.117536] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Revised: 10/10/2020] [Accepted: 10/28/2020] [Indexed: 01/15/2023] Open
Abstract
Healthy aging is associated with mechanistic changes in gamma-aminobutyric acid (GABA), the most abundant inhibitory neurotransmitter in the human brain. While previous work mainly focused on magnetic resonance spectroscopy (MRS)-based GABA+ levels and transcranial magnetic stimulation (TMS)-based GABAA receptor (GABAAR) activity in the primary sensorimotor (SM1) cortex, the aim of the current study was to identify age-related differences in positron emission tomography (PET)-based GABAAR availability and its relationship with GABA+ levels (i.e. GABA with the contribution of macromolecules) and GABAAR activity. For this purpose, fifteen young (aged 20–28 years) and fifteen older (aged 65–80 years) participants were recruited. PET and MRS images were acquired using simultaneous time-of-flight PET/MR to evaluate age-related differences in GABAAR availability (distribution volume ratio with pons as reference region) and GABA+ levels. TMS was applied to identify age-related differences in GABAAR activity by measuring short-interval intracortical inhibition (SICI). Whereas GABAAR availability was significantly higher in the SM cortex of older as compared to young adults (18.5%), there were neither age-related differences in GABA+ levels nor SICI. A correlation analysis revealed no significant associations between GABAAR availability, GABAAR activity and GABA+ levels. Although the exact mechanisms need to be further elucidated, it is possible that a higher GABAAR availability in older adults is a compensatory mechanism to ensure optimal inhibitory functionality during the aging process.
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69
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Pavlov AN, Pitsik EN, Frolov NS, Badarin A, Pavlova ON, Hramov AE. Age-Related Distinctions in EEG Signals during Execution of Motor Tasks Characterized in Terms of Long-Range Correlations. SENSORS 2020; 20:s20205843. [PMID: 33076556 PMCID: PMC7602706 DOI: 10.3390/s20205843] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 09/23/2020] [Accepted: 10/12/2020] [Indexed: 12/20/2022]
Abstract
The problem of revealing age-related distinctions in multichannel electroencephalograms (EEGs) during the execution of motor tasks in young and elderly adults is addressed herein. Based on the detrended fluctuation analysis (DFA), differences in long-range correlations are considered, emphasizing changes in the scaling exponent α. Stronger responses in elderly subjects are confirmed, including the range and rate of increase in α. Unlike elderly subjects, young adults demonstrated about 2.5 times more pronounced differences between motor task responses with the dominant and non-dominant hand. Knowledge of age-related changes in brain electrical activity is important for understanding consequences of healthy aging and distinguishing them from pathological changes associated with brain diseases. Besides diagnosing age-related effects, the potential of DFA can also be used in the field of brain–computer interfaces.
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Affiliation(s)
- Alexey N. Pavlov
- Saratov State University, Astrakhanskaya Str. 83, 410012 Saratov, Russia; (A.N.P.); (O.N.P.)
| | - Elena N. Pitsik
- Neuroscience and Cognitive Technology Laboratory, Center for Technologies in Robotics and Mechatronics Components, Innopolis University, Universitetskaya Str. 1, 420500 Innopolis, Russia; (E.N.P.); (N.S.F.); (A.B.)
| | - Nikita S. Frolov
- Neuroscience and Cognitive Technology Laboratory, Center for Technologies in Robotics and Mechatronics Components, Innopolis University, Universitetskaya Str. 1, 420500 Innopolis, Russia; (E.N.P.); (N.S.F.); (A.B.)
| | - Artem Badarin
- Neuroscience and Cognitive Technology Laboratory, Center for Technologies in Robotics and Mechatronics Components, Innopolis University, Universitetskaya Str. 1, 420500 Innopolis, Russia; (E.N.P.); (N.S.F.); (A.B.)
| | - Olga N. Pavlova
- Saratov State University, Astrakhanskaya Str. 83, 410012 Saratov, Russia; (A.N.P.); (O.N.P.)
| | - Alexander E. Hramov
- Neuroscience and Cognitive Technology Laboratory, Center for Technologies in Robotics and Mechatronics Components, Innopolis University, Universitetskaya Str. 1, 420500 Innopolis, Russia; (E.N.P.); (N.S.F.); (A.B.)
- Lobachevsky University, 23 Gagarina Avenue, 603950 Nizhny Novgorod, Russia
- Saratov State Medical University, Bolshaya Kazachya Str. 112, 410012 Saratov, Russia
- Correspondence:
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70
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Lund MJ, Alnæs D, Schwab S, van der Meer D, Andreassen OA, Westlye LT, Kaufmann T. Differences in directed functional brain connectivity related to age, sex and mental health. Hum Brain Mapp 2020; 41:4173-4186. [PMID: 32613721 PMCID: PMC7502836 DOI: 10.1002/hbm.25116] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 06/07/2020] [Accepted: 06/16/2020] [Indexed: 01/09/2023] Open
Abstract
Functional interconnections between brain regions define the "connectome" which is of central interest for understanding human brain function. Resting-state functional magnetic resonance (rsfMRI) work has revealed changes in static connectivity related to age, sex, cognitive abilities and psychiatric symptoms, yet little is known how these factors may alter the information flow. The commonly used approach infers functional brain connectivity using stationary coefficients yielding static estimates of the undirected connection strength between brain regions. Dynamic graphical models (DGMs) are a multivariate model with dynamic coefficients reflecting directed temporal associations between nodes, and can yield novel insight into directed functional connectivity. Here, we leveraged this approach to test for associations between edge-wise estimates of direction flow across the functional connectome and age, sex, intellectual abilities and mental health. We applied DGM to investigate patterns of information flow in data from 984 individuals from the Human Connectome Project (HCP) and 10,249 individuals from the UK Biobank. Our analysis yielded patterns of directed connectivity in independent HCP and UK Biobank data similar to those previously reported, including that the cerebellum consistently receives information from other networks. We show robust associations between information flow and age and sex for several connections, with strongest effects of age observed in the sensorimotor network. Visual, auditory and sensorimotor nodes were also linked to mental health. Our findings support the use of DGM as a measure of directed connectivity in rsfMRI data and provide new insight into the shaping of the connectome during aging.
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Affiliation(s)
- Martina J. Lund
- Norwegian Centre for Mental Disorders Research (NORMENT), Division of Mental Health and AddictionOslo University Hospital, and Institute of Clinical Medicine, University of OsloOsloNorway
| | - Dag Alnæs
- Norwegian Centre for Mental Disorders Research (NORMENT), Division of Mental Health and AddictionOslo University Hospital, and Institute of Clinical Medicine, University of OsloOsloNorway
- Bjørknes University CollegeOsloNorway
| | - Simon Schwab
- Center for Reproducible Science (CRS) & Epidemiology, Biostatistics and Prevention Institute (EBPI)University of ZürichZurichSwitzerland
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Population HealthUniversity of OxfordOxfordUK
| | - Dennis van der Meer
- Norwegian Centre for Mental Disorders Research (NORMENT), Division of Mental Health and AddictionOslo University Hospital, and Institute of Clinical Medicine, University of OsloOsloNorway
- School of Mental Health and Neuroscience, Faculty of Health, Medicine and Life SciencesMaastricht UniversityMaastrichtThe Netherlands
| | - Ole A. Andreassen
- Norwegian Centre for Mental Disorders Research (NORMENT), Division of Mental Health and AddictionOslo University Hospital, and Institute of Clinical Medicine, University of OsloOsloNorway
- KG Jebsen Centre for neurodevelopmental disorders, University of OsloOsloNorway
| | - Lars T. Westlye
- Norwegian Centre for Mental Disorders Research (NORMENT), Division of Mental Health and AddictionOslo University Hospital, and Institute of Clinical Medicine, University of OsloOsloNorway
- KG Jebsen Centre for neurodevelopmental disorders, University of OsloOsloNorway
- Department of PsychologyUniversity of OsloOsloNorway
| | - Tobias Kaufmann
- Norwegian Centre for Mental Disorders Research (NORMENT), Division of Mental Health and AddictionOslo University Hospital, and Institute of Clinical Medicine, University of OsloOsloNorway
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71
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Steel A, Mikkelsen M, Edden RAE, Robertson CE. Regional balance between glutamate+glutamine and GABA+ in the resting human brain. Neuroimage 2020; 220:117112. [PMID: 32619710 PMCID: PMC9652611 DOI: 10.1016/j.neuroimage.2020.117112] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 06/17/2020] [Accepted: 06/27/2020] [Indexed: 12/04/2022] Open
Abstract
Models of healthy brain function and psychiatric conditions assume that excitatory and inhibitory activity are balanced in the human brain at multiple spatial and temporal scales. In human neuroimaging, concentrations of the major excitatory (glutamate) and inhibitory (γ-aminobutyric acid, GABA) neurotransmitters are measured in vivo using magnetic resonance spectroscopy (MRS). However, despite the central importance of E/I balance to theories of brain function, a relationship between regional glutamate and GABA levels in the human brain has not been shown. We addressed this question in a large corpus of edited MRS data collected at 19 different sites (n = 220). Consistent with the notion of E/I balance, we found that levels of glutamate+glutamine (Glx) and GABA+ were highly correlated (R = 0.52, p = 2.86 x 10−14). This relationship held when controlling for site, scanner vendor, and demographics. Controlling for neurochemicals associated with neuronal density and metabolism (i.e. N-acetylaspartate and creatine) significantly reduced the correlation between GABA+ and Glx, suggesting that the levels of GABA+ and Glx may be critically linked to regional metabolism. These results are consistent with the notion that excitation and inhibition are balanced in the human brain.
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Affiliation(s)
- Adam Steel
- Department of Psychology and Brain Sciences, Dartmouth College, Hanover, NH, USA.
| | - Mark Mikkelsen
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Richard A E Edden
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Caroline E Robertson
- Department of Psychology and Brain Sciences, Dartmouth College, Hanover, NH, USA
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72
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van Vugt FT, Near J, Hennessy T, Doyon J, Ostry DJ. Early stages of sensorimotor map acquisition: neurochemical signature in primary motor cortex and its relation to functional connectivity. J Neurophysiol 2020; 124:1615-1624. [PMID: 32997558 DOI: 10.1152/jn.00285.2020] [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] [Indexed: 12/25/2022] Open
Abstract
The earliest stages of sensorimotor learning involve learning the correspondence between movements and sensory results-a sensorimotor map. The present exploratory study investigated the neurochemical underpinnings of map acquisition by monitoring 25 participants as they acquired a new association between movements and sounds. Functional magnetic resonance spectroscopy was used to measure neurochemical concentrations in the left primary motor cortex during learning. Resting-state functional magnetic resonance imaging data were also collected before and after training to assess learning-related changes in functional connectivity. There were monotonic increases in γ-aminobutyric acid (GABA) and decreases in glucose during training, which extended into the subsequent rest period and, importantly, in the case of GABA correlated with the amount of learning: participants who showed greater behavioral learning showed greater GABA increase. The GABA change was furthermore correlated with changes in functional connectivity between the primary motor cortex and a cluster of voxels in the right intraparietal sulcus: greater increases in GABA were associated with greater strengthening of connectivity. Transiently, there were increases in lactate and reductions in aspartate, which returned to baseline at the end of training, but only lactate showed a statistical trend to correlate with the amount of learning. In summary, during the earliest stages of sensorimotor learning, GABA levels are linked on a subject-level basis to both behavioral learning and a strengthening of functional connections that persists beyond the training period. The findings are consistent with the idea that GABA-mediated inhibition is linked to maintenance of newly learned information.NEW & NOTEWORTHY Learning the mapping between movements and their sensory effects is a necessary step in the early stages of sensorimotor learning. There is evidence showing which brain areas are involved in early motor learning, but their role remains uncertain. Here, we show that GABA, a neurotransmitter linked to inhibitory processing, rises during and after learning and is involved in ongoing changes in resting-state networks.
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Affiliation(s)
- F T van Vugt
- Department of Psychology, McGill University, Montreal, Quebec, Canada.,Haskins Laboratories, New Haven, Connecticut.,Department of Psychology, University of Montreal, Montreal, Quebec, Canada
| | - J Near
- Douglas Mental Health University Institute, Montreal, Quebec, Canada.,Department of Biomechanical Engineering, McGill University, Montreal, Quebec, Canada
| | - T Hennessy
- Douglas Mental Health University Institute, Montreal, Quebec, Canada.,Department of Biomechanical Engineering, McGill University, Montreal, Quebec, Canada
| | - J Doyon
- Department of Psychology, University of Montreal, Montreal, Quebec, Canada.,Unité de Neuroimagerie Fonctionnelle, Centre de recherche, Institut universitaire de gériatrie de Montréal, Montreal, Quebec, Canada.,Department Of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
| | - D J Ostry
- Department of Psychology, McGill University, Montreal, Quebec, Canada.,Haskins Laboratories, New Haven, Connecticut
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73
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Functional network reorganization in older adults: Graph-theoretical analyses of age, cognition and sex. Neuroimage 2020; 214:116756. [DOI: 10.1016/j.neuroimage.2020.116756] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 02/28/2020] [Accepted: 03/14/2020] [Indexed: 01/21/2023] Open
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74
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Wen X, He H, Dong L, Chen J, Yang J, Guo H, Luo C, Yao D. Alterations of local functional connectivity in lifespan: A resting-state fMRI study. Brain Behav 2020; 10:e01652. [PMID: 32462815 PMCID: PMC7375100 DOI: 10.1002/brb3.1652] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 04/08/2020] [Accepted: 04/13/2020] [Indexed: 12/24/2022] Open
Abstract
INTRODUCTION As aging attracted attention globally, revealing changes in brain function across the lifespan was largely concerned. In this study, we aimed to reveal the changes of functional networks of the brain (via local functional connectivity, local FC) in lifespan and explore the mechanism underlying them. MATERIALS AND METHODS A total of 523 healthy participants (258 males and 265 females) aged 18-88 years from part of the Cambridge Center for Ageing and Neuroscience (CamCAN) were involved in this study. Next, two data-driven measures of local FC, local functional connectivity density (lFCD) and four-dimensional spatial-temporal consistency of local neural activity (FOCA), were calculated, and then, general linear models were used to assess the changes of them in lifespan. RESULTS Local functional connectivity (lFCD and FOCA) within visual networks (VN), sensorimotor network (SMN), and default mode network (DMN) decreased across the lifespan, while within basal ganglia network (BGN), local connectivity was increased across the lifespan. And, the fluid intelligence decreased within BGN while increased within VN, SMN, and DMN. CONCLUSION These results might suggest that the decline of executive control and intrinsic cognitive ability in the aging population was related to the decline of functional connectivity in VN, SMN, and DMN. Meanwhile, BGN might play a regulatory role in the aging process to compensate for the dysfunction of other functional systems. Our findings may provide important neuroimaging evidence for exploring the brain functional mechanism in lifespan.
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Affiliation(s)
- Xin Wen
- College of Information and Computer, Taiyuan University of Technology, Taiyuan, China
| | - Hui He
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for Neuroinformation, University of Electronic Science and Technology of China, Chengdu, China
| | - Li Dong
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for Neuroinformation, University of Electronic Science and Technology of China, Chengdu, China.,School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China
| | - Junjie Chen
- College of Information and Computer, Taiyuan University of Technology, Taiyuan, China
| | - Jie Yang
- School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China
| | - Hao Guo
- College of Information and Computer, Taiyuan University of Technology, Taiyuan, China
| | - Cheng Luo
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for Neuroinformation, University of Electronic Science and Technology of China, Chengdu, China.,School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China
| | - Dezhong Yao
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for Neuroinformation, University of Electronic Science and Technology of China, Chengdu, China.,School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China
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75
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King BR, Rumpf JJ, Verbaanderd E, Heise KF, Dolfen N, Sunaert S, Doyon J, Classen J, Mantini D, Puts NAJ, Edden RAE, Albouy G, Swinnen SP. Baseline sensorimotor GABA levels shape neuroplastic processes induced by motor learning in older adults. Hum Brain Mapp 2020; 41:3680-3695. [PMID: 32583940 PMCID: PMC7416055 DOI: 10.1002/hbm.25041] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 05/04/2020] [Accepted: 05/09/2020] [Indexed: 12/12/2022] Open
Abstract
Previous research in young adults has demonstrated that both motor learning and transcranial direct current stimulation (tDCS) trigger decreases in the levels of gamma-aminobutyric acid (GABA) in the sensorimotor cortex, and these decreases are linked to greater learning. Less is known about the role of GABA in motor learning in healthy older adults, a knowledge gap that is surprising given the established aging-related reductions in sensorimotor GABA. Here, we examined the effects of motor learning and subsequent tDCS on sensorimotor GABA levels and resting-state functional connectivity in the brains of healthy older participants. Thirty-six older men and women completed a motor sequence learning task before receiving anodal or sham tDCS to the sensorimotor cortex. GABA-edited magnetic resonance spectroscopy of the sensorimotor cortex and resting-state (RS) functional magnetic resonance imaging data were acquired before and after learning/stimulation. At the group level, neither learning nor anodal tDCS significantly modulated GABA levels or RS connectivity among task-relevant regions. However, changes in GABA levels from the baseline to post-learning session were significantly related to motor learning magnitude, age, and baseline GABA. Moreover, the change in functional connectivity between task-relevant regions, including bilateral motor cortices, was correlated with baseline GABA levels. These data collectively indicate that motor learning-related decreases in sensorimotor GABA levels and increases in functional connectivity are limited to those older adults with higher baseline GABA levels and who learn the most. Post-learning tDCS exerted no influence on GABA levels, functional connectivity or the relationships among these variables in older adults.
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Affiliation(s)
- Bradley R King
- Department of Movement Sciences, Movement Control and Neuroplasticity Research Group, KU Leuven, Leuven, Belgium.,LBI-KU Leuven Brain Institute, Leuven, Belgium
| | | | - Elvire Verbaanderd
- Department of Movement Sciences, Movement Control and Neuroplasticity Research Group, KU Leuven, Leuven, Belgium
| | - Kirstin F Heise
- Department of Movement Sciences, Movement Control and Neuroplasticity Research Group, KU Leuven, Leuven, Belgium.,LBI-KU Leuven Brain Institute, Leuven, Belgium
| | - Nina Dolfen
- Department of Movement Sciences, Movement Control and Neuroplasticity Research Group, KU Leuven, Leuven, Belgium.,LBI-KU Leuven Brain Institute, Leuven, Belgium
| | - Stefan Sunaert
- Department of Imaging and Pathology, KU Leuven and University Hospital Leuven (UZ Leuven), Leuven, Belgium
| | - Julien Doyon
- McConnell Brain Imaging Center, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Joseph Classen
- Department of Neurology, University of Leipzig, Leipzig, Germany
| | - Dante Mantini
- Department of Movement Sciences, Movement Control and Neuroplasticity Research Group, KU Leuven, Leuven, Belgium.,LBI-KU Leuven Brain Institute, Leuven, Belgium.,Brain Imaging and Neural Dynamics Research Group, IRCCS San Camillo Hospital, Venice, Italy
| | - Nicolaas A J Puts
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA.,Department of Forensic and Neurodevelopmental Sciences, The Institute of Psychiatry, Psychology, and Neuroscience, King's College London, London, UK
| | - Richard A E Edden
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Geneviève Albouy
- Department of Movement Sciences, Movement Control and Neuroplasticity Research Group, KU Leuven, Leuven, Belgium.,LBI-KU Leuven Brain Institute, Leuven, Belgium
| | - Stephan P Swinnen
- Department of Movement Sciences, Movement Control and Neuroplasticity Research Group, KU Leuven, Leuven, Belgium.,LBI-KU Leuven Brain Institute, Leuven, Belgium
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76
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Manza P, Wiers CE, Shokri-Kojori E, Kroll D, Feldman D, Schwandt M, Wang GJ, Tomasi D, Volkow ND. Brain Network Segregation and Glucose Energy Utilization: Relevance for Age-Related Differences in Cognitive Function. Cereb Cortex 2020; 30:5930-5942. [PMID: 32564073 DOI: 10.1093/cercor/bhaa167] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 05/27/2020] [Accepted: 05/27/2020] [Indexed: 12/19/2022] Open
Abstract
The human brain is organized into segregated networks with strong within-network connections and relatively weaker between-network connections. This "small-world" organization may be essential for maintaining an energetically efficient system, crucial to the brain which consumes 20% of the body's energy. Brain network segregation and glucose energy utilization both change throughout the lifespan. However, it remains unclear whether these processes interact to contribute to differences in cognitive performance with age. To address this, we examined fluorodeoxyglucose-positron emission tomography and resting-state functional magnetic resonance imaging from 88 participants aged 18-73 years old. Consistent with prior work, brain network segregation showed a negative association with age across both sensorimotor and association networks. However, relative glucose metabolism demonstrated an interaction with age, showing a negative slope in association networks but a positive slope in sensorimotor networks. Overall, brain networks with lower segregation showed significantly steeper age-related differences in glucose metabolism, compared with highly segregated networks. Sensorimotor network segregation mediated the association between age and poorer spatial cognition performance, and sensorimotor network metabolism mediated the association between age and slower response time. These data provide evidence that sensorimotor segregation and glucose metabolism underlie some age-related changes in cognition. Interventions that stimulate somatosensory networks could be important for treatment of age-related cognitive decline.
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Affiliation(s)
- Peter Manza
- National Institute on Alcoholism and Alcohol Abuse, National Institutes of Health, Bethesda, MD 20892, USA
| | - Corinde E Wiers
- National Institute on Alcoholism and Alcohol Abuse, National Institutes of Health, Bethesda, MD 20892, USA
| | - Ehsan Shokri-Kojori
- National Institute on Alcoholism and Alcohol Abuse, National Institutes of Health, Bethesda, MD 20892, USA
| | - Danielle Kroll
- National Institute on Alcoholism and Alcohol Abuse, National Institutes of Health, Bethesda, MD 20892, USA
| | - Dana Feldman
- National Institute on Alcoholism and Alcohol Abuse, National Institutes of Health, Bethesda, MD 20892, USA
| | - Melanie Schwandt
- National Institute on Alcoholism and Alcohol Abuse, National Institutes of Health, Bethesda, MD 20892, USA
| | - Gene-Jack Wang
- National Institute on Alcoholism and Alcohol Abuse, National Institutes of Health, Bethesda, MD 20892, USA
| | - Dardo Tomasi
- National Institute on Alcoholism and Alcohol Abuse, National Institutes of Health, Bethesda, MD 20892, USA
| | - Nora D Volkow
- National Institute on Alcoholism and Alcohol Abuse, National Institutes of Health, Bethesda, MD 20892, USA.,National Institute on Drug Abuse, National Institutes of Health, Bethesda, MD 20892, USA
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77
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Cassady K, Gagnon H, Freiburger E, Lalwani P, Simmonite M, Park DC, Peltier SJ, Taylor SF, Weissman DH, Seidler RD, Polk TA. Network segregation varies with neural distinctiveness in sensorimotor cortex. Neuroimage 2020; 212:116663. [PMID: 32109601 PMCID: PMC7723993 DOI: 10.1016/j.neuroimage.2020.116663] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 01/09/2020] [Accepted: 02/16/2020] [Indexed: 11/26/2022] Open
Abstract
Normal aging is associated with declines in sensorimotor function. Previous studies have linked age-related behavioral declines to decreases in neural differentiation (i.e., dedifferentiation), including decreases in the distinctiveness of neural activation patterns and in the segregation of large-scale neural networks at rest. However, no studies to date have explored the relationship between these two neural measures and whether they explain the same aspects of behavior. To investigate these issues, we collected a battery of sensorimotor behavioral measures in older and younger adults and estimated (a) the distinctiveness of neural representations in sensorimotor cortex and (b) sensorimotor network segregation in the same participants. Consistent with prior findings, sensorimotor representations were less distinct and sensorimotor resting state networks were less segregated in older compared to younger adults. We also found that participants with the most distinct sensorimotor representations exhibited the most segregated sensorimotor networks. However, only sensorimotor network segregation was associated with individual differences in sensorimotor performance, particularly in older adults. These novel findings link network segregation to neural distinctiveness, but also suggest that network segregation may play a larger role in maintaining sensorimotor performance with age.
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Affiliation(s)
- Kaitlin Cassady
- Department of Psychology, University of Michigan, Ann Arbor, MI, USA.
| | - Holly Gagnon
- Department of Psychology, University of Utah, Salt Lake City, UT, USA
| | - Erin Freiburger
- Department of Psychology, University of Michigan, Ann Arbor, MI, USA
| | - Poortata Lalwani
- Department of Psychology, University of Michigan, Ann Arbor, MI, USA
| | - Molly Simmonite
- Department of Psychology, University of Michigan, Ann Arbor, MI, USA
| | - Denise C Park
- Research of the Center for Vital Longevity, University of Texas at Dallas, Dallas, TX, USA
| | - Scott J Peltier
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Stephan F Taylor
- Department of Psychology, University of Michigan, Ann Arbor, MI, USA; Department of Psychiatry, University of Michigan, Ann Arbor, MI, USA
| | - Daniel H Weissman
- Department of Psychology, University of Michigan, Ann Arbor, MI, USA
| | - Rachael D Seidler
- Department of Applied Physiology & Kinesiology, University of Florida, Gainesville, FL, USA
| | - Thad A Polk
- Department of Psychology, University of Michigan, Ann Arbor, MI, USA
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78
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Muscle Mass and Muscle Strength Relationships to Balance: The Role of Age and Physical Activity. J Aging Phys Act 2020; 28:262-268. [PMID: 31585435 DOI: 10.1123/japa.2018-0113] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Revised: 05/07/2019] [Accepted: 07/18/2019] [Indexed: 11/18/2022]
Abstract
OBJECTIVE To investigate the relations of balance to muscle mass (MM) and muscle strength (MS), depending on age and physical activity, which is of particular importance to functional independence in older people. METHODS This cross-sectional study included 802 volunteers (69.82 ± 5.60 years). The Fullerton Advanced Balance scale was used to assess balance and a composite score, including arm curl and chair stand tests for assessing MS. MM was estimated by dual-energy X-ray absorptiometry and physical activity by questionnaire. RESULTS Greater MM (r = .26, p < .001) and MS (r = .53, p < .001) were positively correlated to balance. The old-old adults and less active individuals attained lower balance. Notably, moderation and subsequent simple slope analyses revealed that the relations of balance, MM, and MS were larger in less active and the old-old adults. CONCLUSIONS The old-old and less active adults were more prone to muscle weakness and balance impairments. Tailored interventions should particularly consider these vulnerable groups.
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79
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Proskovec AL, Spooner RK, Wiesman AI, Wilson TW. Local cortical thickness predicts somatosensory gamma oscillations and sensory gating: A multimodal approach. Neuroimage 2020; 214:116749. [PMID: 32199953 DOI: 10.1016/j.neuroimage.2020.116749] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 02/26/2020] [Accepted: 03/13/2020] [Indexed: 12/24/2022] Open
Abstract
Two largely distinct bodies of research have demonstrated age-related alterations and disease-specific aberrations in both local gamma oscillations and patterns of cortical thickness. However, seldom has the relationship between gamma activity and cortical thickness been investigated. Herein, we combine the spatiotemporal precision of magnetoencephalography (MEG) with high-resolution magnetic resonance imaging and surface-based morphometry to characterize the relationships between somatosensory gamma oscillations and the thickness of the cortical tissue generating the oscillations in 94 healthy adults (age range: 22-72). Specifically, a series of regressions were computed to assess the relationships between thickness of the primary somatosensory cortex (S1), S1 gamma response power, peak gamma frequency, and somatosensory gating of identical stimuli. Our results indicated that increased S1 thickness significantly predicted greater S1 gamma response power, reduced peak gamma frequency, and improved somatosensory gating. Furthermore, peak gamma frequency significantly and partially mediated the relationship between S1 thickness and the magnitude of the S1 gamma response. Finally, advancing age significantly predicted reduced S1 thickness and decreased gating of redundant somatosensory stimuli. Notably, this is the first study to directly link somatosensory gamma oscillations to local cortical thickness. Our results demonstrate a multi-faceted relationship between structure and function, and have important implications for understanding age- and disease-related deficits in basic sensory processing and higher-order inhibitory function.
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Affiliation(s)
- Amy L Proskovec
- Center for Magnetoencephalography, University of Nebraska Medical Center (UNMC), Omaha, NE, 68198, USA; Department of Neurological Sciences, UNMC, Omaha, NE, 68198, USA; Department of Psychology, University of Nebraska - Omaha, Omaha, NE, 68182, USA; Magnetoencephalography Center of Excellence, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA.
| | - Rachel K Spooner
- Center for Magnetoencephalography, University of Nebraska Medical Center (UNMC), Omaha, NE, 68198, USA; Department of Neurological Sciences, UNMC, Omaha, NE, 68198, USA
| | - Alex I Wiesman
- Center for Magnetoencephalography, University of Nebraska Medical Center (UNMC), Omaha, NE, 68198, USA; Department of Neurological Sciences, UNMC, Omaha, NE, 68198, USA
| | - Tony W Wilson
- Center for Magnetoencephalography, University of Nebraska Medical Center (UNMC), Omaha, NE, 68198, USA; Department of Neurological Sciences, UNMC, Omaha, NE, 68198, USA; Department of Psychology, University of Nebraska - Omaha, Omaha, NE, 68182, USA
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80
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Monteiro TS, Zivari Adab H, Chalavi S, Gooijers J, King BBR, Cuypers K, Mantini D, Swinnen SP. Reduced Modulation of Task-Related Connectivity Mediates Age-Related Declines in Bimanual Performance. Cereb Cortex 2020; 30:4346-4360. [PMID: 32133505 DOI: 10.1093/cercor/bhaa021] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Aging is accompanied by marked changes in motor behavior and its neural correlates. At the behavioral level, age-related declines in motor performance manifest, for example, as a reduced capacity to inhibit interference between hands during bimanual movements, particularly when task complexity increases. At the neural level, aging is associated with reduced differentiation between distinct functional systems. Functional connectivity (FC) dedifferentiation is characterized by more homogeneous connectivity patterns across various tasks or task conditions, reflecting a reduced ability of the aging adult to modulate brain activity according to changing task demands. It is currently unknown, however, how whole-brain dedifferentiation interacts with increasing task complexity. In the present study, we investigated age- and task-related FC in a group of 96 human adults across a wide age range (19.9-74.5 years of age) during the performance of a bimanual coordination task of varying complexity. Our findings indicated stronger task complexity-related differentiation between visuomotor- and nonvisuomotor-related networks, though modulation capability decreased with increasing age. Decreased FC modulation mediated larger complexity-related increases in between-hand interference, reflective of worse bimanual coordination. Thus, the ability to maintain high motor performance levels in older adults is related to the capability to properly segregate and modulate functional networks.
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Affiliation(s)
- Thiago Santos Monteiro
- Research Center for Movement Control and Neuroplasticity, Department of Movement Sciences, Biomedical Sciences Group, KU Leuven, Leuven, Belgium.,Leuven Brain Institute (LBI), KU Leuven, Leuven, Belgium
| | - Hamed Zivari Adab
- Research Center for Movement Control and Neuroplasticity, Department of Movement Sciences, Biomedical Sciences Group, KU Leuven, Leuven, Belgium.,Leuven Brain Institute (LBI), KU Leuven, Leuven, Belgium
| | - Sima Chalavi
- Research Center for Movement Control and Neuroplasticity, Department of Movement Sciences, Biomedical Sciences Group, KU Leuven, Leuven, Belgium.,Leuven Brain Institute (LBI), KU Leuven, Leuven, Belgium
| | - Jolien Gooijers
- Research Center for Movement Control and Neuroplasticity, Department of Movement Sciences, Biomedical Sciences Group, KU Leuven, Leuven, Belgium.,Leuven Brain Institute (LBI), KU Leuven, Leuven, Belgium
| | - Brad Bradley Ross King
- Research Center for Movement Control and Neuroplasticity, Department of Movement Sciences, Biomedical Sciences Group, KU Leuven, Leuven, Belgium.,Leuven Brain Institute (LBI), KU Leuven, Leuven, Belgium
| | - Koen Cuypers
- Research Center for Movement Control and Neuroplasticity, Department of Movement Sciences, Biomedical Sciences Group, KU Leuven, Leuven, Belgium.,Leuven Brain Institute (LBI), KU Leuven, Leuven, Belgium.,REVAL Research Institute, Hasselt University, Diepenbeek, Belgium
| | - Dante Mantini
- Research Center for Movement Control and Neuroplasticity, Department of Movement Sciences, Biomedical Sciences Group, KU Leuven, Leuven, Belgium.,Leuven Brain Institute (LBI), KU Leuven, Leuven, Belgium.,Brain Imaging and Neural Dynamics Research Group, IRCCS San Camillo Hospital, Venice, Italy
| | - Stephan Patrick Swinnen
- Research Center for Movement Control and Neuroplasticity, Department of Movement Sciences, Biomedical Sciences Group, KU Leuven, Leuven, Belgium.,Leuven Brain Institute (LBI), KU Leuven, Leuven, Belgium
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81
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Abstract
This review focuses on possible contributions of neural dedifferentiation to age-related cognitive decline. Neural dedifferentiation is held to reflect a breakdown in the functional specificity of brain regions and networks that compromises the fidelity of neural representations supporting episodic memory and related cognitive functions. The evidence for age-related dedifferentiation is robust when it is operationalized as neural selectivity for different categories of perceptual stimuli or as decreased segregation or modularity of resting-state functional brain networks. Neural dedifferentiation for perceptual categories appears to demonstrate a negative, age-invariant relationship with performance on tests of memory and fluid processing. Whether this pattern extends to network-level measures of dedifferentiation cannot currently be determined due to insufficient evidence. The existing data highlight the importance of further examination of neural dedifferentiation as a factor contributing to episodic memory and to cognitive performance more generally.
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82
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Zuo N, Salami A, Liu H, Yang Z, Jiang T. Functional maintenance in the multiple demand network characterizes superior fluid intelligence in aging. Neurobiol Aging 2020; 85:145-153. [DOI: 10.1016/j.neurobiolaging.2019.09.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 08/20/2019] [Accepted: 09/14/2019] [Indexed: 12/13/2022]
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83
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Muller AM, Meyerhoff DJ. Does an Over-Connected Visual Cortex Undermine Efforts to Stay Sober After Treatment for Alcohol Use Disorder? Front Psychiatry 2020; 11:536706. [PMID: 33362591 PMCID: PMC7758478 DOI: 10.3389/fpsyt.2020.536706] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 11/11/2020] [Indexed: 11/13/2022] Open
Abstract
A fine-tuned interplay of highly synchronized activity within and between the brain's communities is a crucial feature of the brain's functional organization. We wanted to investigate in individuals with alcohol use disorder (AUD) the degree to which the interplay of the brain's community-architecture and the extended brain reward system (eBRS) is affected by drinking status (relapse or abstinence). We used Graph Theory Analysis of resting-state fMRI data from treatment seekers at 1 month of abstinence to model the brain's intrinsic community configuration and their follow-up data as abstainers or relapsers 3 months later to quantify the degree of global across-community interaction between the eBRS and the intrinsic communities at both timepoints. After 1 month of abstinence, the ventromedial PFC in particular showed a significantly higher global across-community interaction in the 22 future relapsers when compared to 30 light/non-drinking controls. These differences were no longer present 3 months later when the relapsers had resumed drinking. We found no significant differences between abstainers and controls at either timepoint. Post hoc tests revealed that one eBRS region, the ventromedial PFC, showed a significant global across-community interaction with a community comprising the visual cortex in relapsers at baseline. In contrast, abstainers showed a significant negative association of the ventromedial PFC with the visual cortex. The increased across-community interaction of the ventromedial PFC and the visual cortex in relapsers at timepoint 1 may be an early indicator for treatment failure in a subgroup of AUD patients.
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Affiliation(s)
- Angela M Muller
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States
| | - Dieter J Meyerhoff
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States
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84
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Cuypers K, Verstraelen S, Maes C, Hermans L, Hehl M, Heise KF, Chalavi S, Mikkelsen M, Edden R, Levin O, Sunaert S, Meesen R, Mantini D, Swinnen SP. Task-related measures of short-interval intracortical inhibition and GABA levels in healthy young and older adults: A multimodal TMS-MRS study. Neuroimage 2019; 208:116470. [PMID: 31863914 PMCID: PMC9652063 DOI: 10.1016/j.neuroimage.2019.116470] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 12/05/2019] [Accepted: 12/15/2019] [Indexed: 01/15/2023] Open
Abstract
Establishing the associations between magnetic resonance spectroscopy (MRS)-assessed gamma-aminobutyric acid (GABA) levels and transcranial magnetic stimulation (TMS)-derived ‘task-related’ modulations in GABAA receptor-mediated inhibition and how these associations change with advancing age is a topic of interest in the field of human neuroscience. In this study, we identified the relationship between GABA levels and task-related modulations in GABAA receptor-mediated inhibition in the dominant (left) and non-dominant (right) sensorimotor (SM) cortices. GABA levels were measured using edited MRS and task-related GABAA receptor-mediated inhibition was measured using a short-interval intracortical inhibition (SICI) TMS protocol during the preparation and premotor period of a choice reaction time (CRT) task in 25 young (aged 18–33 years) and 25 older (aged 60–74 years) adults. Our results demonstrated that GABA levels in both SM voxels were lower in older adults as compared to younger adults; and higher SM GABA levels in the dominant as compared to the non-dominant SM voxel pointed to a lateralization effect, irrespective of age group. Furthermore, older adults showed decreased GABAA receptor-mediated inhibition in the preparation phase of the CRT task within the dominant primary motor cortex (M1), as compared to young adults. Finally, results from an exploratory correlation analysis pointed towards positive relationships between MRS-assessed GABA levels and TMS-derived task-related SICI measures. However, after correction for multiple comparisons none of the correlations remained significant.
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Affiliation(s)
- K Cuypers
- Movement Control & Neuroplasticity Research Group, Department of Movement Sciences, Group Biomedical Sciences, KU Leuven, 3001, Heverlee, Belgium; REVAL Research Institute, Hasselt University, Agoralaan, Building A, 3590, Diepenbeek, Belgium.
| | - S Verstraelen
- REVAL Research Institute, Hasselt University, Agoralaan, Building A, 3590, Diepenbeek, Belgium
| | - C Maes
- Movement Control & Neuroplasticity Research Group, Department of Movement Sciences, Group Biomedical Sciences, KU Leuven, 3001, Heverlee, Belgium
| | - L Hermans
- Movement Control & Neuroplasticity Research Group, Department of Movement Sciences, Group Biomedical Sciences, KU Leuven, 3001, Heverlee, Belgium
| | - M Hehl
- Movement Control & Neuroplasticity Research Group, Department of Movement Sciences, Group Biomedical Sciences, KU Leuven, 3001, Heverlee, Belgium
| | - K-F Heise
- Movement Control & Neuroplasticity Research Group, Department of Movement Sciences, Group Biomedical Sciences, KU Leuven, 3001, Heverlee, Belgium
| | - S Chalavi
- Movement Control & Neuroplasticity Research Group, Department of Movement Sciences, Group Biomedical Sciences, KU Leuven, 3001, Heverlee, Belgium
| | - M Mikkelsen
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - R Edden
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - O Levin
- Movement Control & Neuroplasticity Research Group, Department of Movement Sciences, Group Biomedical Sciences, KU Leuven, 3001, Heverlee, Belgium
| | - S Sunaert
- Department of Imaging and Pathology, University Hospitals Leuven, Leuven, Belgium; Department of Radiology, University Hospitals Leuven, Gasthuisberg, UZ, Leuven, Belgium
| | - R Meesen
- Movement Control & Neuroplasticity Research Group, Department of Movement Sciences, Group Biomedical Sciences, KU Leuven, 3001, Heverlee, Belgium; REVAL Research Institute, Hasselt University, Agoralaan, Building A, 3590, Diepenbeek, Belgium
| | - D Mantini
- Movement Control & Neuroplasticity Research Group, Department of Movement Sciences, Group Biomedical Sciences, KU Leuven, 3001, Heverlee, Belgium; Brain Imaging and Neural Dynamics Research Group, IRCCS San Camillo Hospital, Venice, Italy
| | - S P Swinnen
- Movement Control & Neuroplasticity Research Group, Department of Movement Sciences, Group Biomedical Sciences, KU Leuven, 3001, Heverlee, Belgium; KU Leuven, Leuven Brain Institute (LBI), Leuven, Belgium
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85
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Chen Q, Xia Y, Zhuang K, Wu X, Liu G, Qiu J. Decreased inter-hemispheric interactions but increased intra-hemispheric integration during typical aging. Aging (Albany NY) 2019; 11:10100-10115. [PMID: 31761785 PMCID: PMC6914428 DOI: 10.18632/aging.102421] [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: 07/27/2019] [Accepted: 10/28/2019] [Indexed: 11/30/2022]
Abstract
Normal aging is known to be accompanied by decreased segregation across the whole-brain functional network, which is associated with cognitive decline. Although compelling evidence supports reduced segregation and increased integration in whole-brain functional connectivity with aging, the age effect on the reorganization of large-scale functional networks at the hemispheric level remains unclear. Here, we aimed to examine age-related differences in inter-hemispheric interactions and intra-hemispheric integration by using resting-state functional MRI data of a healthy adult lifespan sample. The results showed that age-related decreases in inter-hemispheric integration were found in entire functional networks in both hemispheres, except for the sensorimotor network (SMN) and posterior default mode network (DMN). Specifically, aging was accompanied by increasing inter-hemispheric segregation in the left frontoparietal network (FPN) and left ventral attention network (VAN), as well as right-brain networks located in the auditory network (AN), visual network (VN), and temporal parts of the DMN. Moreover, aging was associated with increasing intra-hemispheric integration within the bilateral VN and posterior DMN while decreasing intra-hemispheric integration within the right VAN. These remarkable changes with aging confirm that there are dynamic interactions between functional networks across the lifespan and provide a means of investigating the mechanisms of cognitive aging.
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Affiliation(s)
- Qunlin Chen
- School of Mathematics and Statistics, Southwest University, Chongqing, China.,Key Laboratory of Cognition and Personality, Ministry of Education, Chongqing, China.,School of Psychology, Southwest University, Chongqing, China
| | - Yunman Xia
- State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, China
| | - Kaixiang Zhuang
- Key Laboratory of Cognition and Personality, Ministry of Education, Chongqing, China.,School of Psychology, Southwest University, Chongqing, China
| | - Xinran Wu
- Key Laboratory of Cognition and Personality, Ministry of Education, Chongqing, China.,School of Psychology, Southwest University, Chongqing, China
| | - Guangyuan Liu
- College of Electronic and Information Engineering, Southwest University, Chongqing, China
| | - Jiang Qiu
- Key Laboratory of Cognition and Personality, Ministry of Education, Chongqing, China.,School of Psychology, Southwest University, Chongqing, China
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86
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Salat DH, Kennedy KM. Current themes and issues in neuroimaging of aging processes: Editorial overview to the special issue on imaging the nonpathological aging brain. Neuroimage 2019; 201:116046. [PMID: 31376520 DOI: 10.1016/j.neuroimage.2019.116046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Affiliation(s)
- David H Salat
- Martinous Center for Biomedical Imaging, Massachusets General Hospital, Department of Radiology, Harvard University, USA
| | - Kristen M Kennedy
- School of Behavioral and Brain Sciences, Center for Vital Longevity, The University of Texas at Dallas, USA.
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87
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Salehi M, Karbasi A, Barron DS, Scheinost D, Constable RT. Individualized functional networks reconfigure with cognitive state. Neuroimage 2019; 206:116233. [PMID: 31574322 DOI: 10.1016/j.neuroimage.2019.116233] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 09/22/2019] [Accepted: 09/27/2019] [Indexed: 02/08/2023] Open
Abstract
There is extensive evidence that functional organization of the human brain varies dynamically as the brain switches between task demands, or cognitive states. This functional organization also varies across subjects, even when engaged in similar tasks. To date, the functional network organization of the brain has been considered static. In this work, we use fMRI data obtained across multiple cognitive states (task-evoked and rest conditions) and across multiple subjects, to measure state- and subject-specific functional network parcellation (the assignment of nodes to networks). Our parcellation approach provides a measure of how node-to-network assignment (NNA) changes across states and across subjects. We demonstrate that the brain's functional networks are not spatially fixed, but that many nodes change their network membership as a function of cognitive state. Such reconfigurations are highly robust and reliable to the extent that they can be used to predict cognitive state with up to 97% accuracy. Our findings suggest that if functional networks are to be defined via functional clustering of nodes, then it is essential to consider that such definitions may be fluid and cognitive-state dependent.
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Affiliation(s)
- Mehraveh Salehi
- Department of Electrical Engineering, Yale University, New Haven, CT, 06511, USA; Yale Institute for Network Science (YINS), Yale University, New Haven, CT, 06511, USA.
| | - Amin Karbasi
- Department of Electrical Engineering, Yale University, New Haven, CT, 06511, USA; Yale Institute for Network Science (YINS), Yale University, New Haven, CT, 06511, USA
| | - Daniel S Barron
- Department of Psychiatry, Yale School of Medicine, New Haven, CT, 06520, USA
| | - Dustin Scheinost
- Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, CT, 06520, USA
| | - R Todd Constable
- Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, CT, 06520, USA; Interdepartmental Neuroscience Program, Yale School of Medicine, New Haven, CT, 06520, USA; Department of Neurosurgery, Yale School of Medicine, New Haven, CT, 06520, USA
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88
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Yuan F, Zhou J, Xu L, Jia W, Chun L, Xu XZS, Liu J. GABA receptors differentially regulate life span and health span in C. elegans through distinct downstream mechanisms. Am J Physiol Cell Physiol 2019; 317:C953-C963. [PMID: 31433690 DOI: 10.1152/ajpcell.00072.2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
GABA, a prominent inhibitory neurotransmitter, is best known to regulate neuronal functions in the nervous system. However, much less is known about the role of GABA signaling in other physiological processes. Interestingly, recent work showed that GABA signaling can regulate life span via a metabotropic GABAB receptor in Caenorhabditis elegans. However, the role of other types of GABA receptors in life span has not been clearly defined. It is also unclear whether GABA signaling regulates health span. Here, using C. elegans as a model, we systematically interrogated the role of various GABA receptors in both life span and health span. We find that mutations in four different GABA receptors extend health span by promoting resistance to stress and pathogen infection and that two such receptor mutants also show extended life span. Different GABA receptors engage distinct transcriptional factors to regulate life span and health span, and even the same receptor regulates life span and health span via different transcription factors. Our results uncover a novel, profound role of GABA signaling in aging in C. elegans, which is mediated by different GABA receptors coupled to distinct downstream effectors.
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Affiliation(s)
- Fengling Yuan
- International Research Center for Sensory Biology and Technology of Ministry of Science and Technology, Key Laboratory of Molecular Biophysics of Ministry of Education, and College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Jiejun Zhou
- International Research Center for Sensory Biology and Technology of Ministry of Science and Technology, Key Laboratory of Molecular Biophysics of Ministry of Education, and College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Lingxiu Xu
- International Research Center for Sensory Biology and Technology of Ministry of Science and Technology, Key Laboratory of Molecular Biophysics of Ministry of Education, and College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Wenxin Jia
- International Research Center for Sensory Biology and Technology of Ministry of Science and Technology, Key Laboratory of Molecular Biophysics of Ministry of Education, and College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Lei Chun
- International Research Center for Sensory Biology and Technology of Ministry of Science and Technology, Key Laboratory of Molecular Biophysics of Ministry of Education, and College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - X Z Shawn Xu
- Life Sciences Institute and Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan
| | - Jianfeng Liu
- International Research Center for Sensory Biology and Technology of Ministry of Science and Technology, Key Laboratory of Molecular Biophysics of Ministry of Education, and College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
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89
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Ruitenberg MFL, Cassady KE, Reuter-Lorenz PA, Tommerdahl M, Seidler RD. Age-Related Reductions in Tactile and Motor Inhibitory Function Start Early but Are Independent. Front Aging Neurosci 2019; 11:193. [PMID: 31417396 PMCID: PMC6682653 DOI: 10.3389/fnagi.2019.00193] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 07/15/2019] [Indexed: 11/13/2022] Open
Abstract
Aging is associated with declines in motor and somatosensory function. Some of these motor declines have been linked to age-related reductions in inhibitory function. Here we examined whether tactile surround inhibition also changes with age and whether these changes are associated with those in the motor domain. We tested a group of 56 participants spanning a wide age range (18-76 years old), allowing us to examine when age differences emerge across the lifespan. Participants performed tactile and motor tasks that have previously been linked to inter- and intra-hemispheric inhibition in the somatosensory and motor systems. The results showed that aging is associated with reductions in inhibitory function in both the tactile and motor systems starting around 40 years of age; however, age effects in the two systems were not correlated. The independent effects of age on tactile and motor inhibitory function suggest that distinct mechanisms may underlie age-related reductions in inhibition in the somatosensory and motor systems.
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Affiliation(s)
- Marit F L Ruitenberg
- Department of Experimental Psychology, Ghent University, Ghent, Belgium.,Department of Health, Medical and Neuropsychology, Leiden University, Leiden, Netherlands
| | - Kaitlin E Cassady
- Department of Psychology, University of Michigan, Ann Arbor, MI, United States
| | | | - Mark Tommerdahl
- Department of Biomedical Engineering, University of North Carolina, Chapel Hill, NC, United States
| | - Rachael D Seidler
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, United States
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90
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Lalwani P, Gagnon H, Cassady K, Simmonite M, Peltier S, Seidler RD, Taylor SF, Weissman DH, Polk TA. Neural distinctiveness declines with age in auditory cortex and is associated with auditory GABA levels. Neuroimage 2019; 201:116033. [PMID: 31326572 DOI: 10.1016/j.neuroimage.2019.116033] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 07/17/2019] [Accepted: 07/17/2019] [Indexed: 12/31/2022] Open
Abstract
Neural activation patterns in the ventral visual cortex in response to different categories of visual stimuli (e.g., faces vs. houses) are less selective, or distinctive, in older adults than in younger adults, a phenomenon known as age-related neural dedifferentiation. In this study, we investigated whether neural dedifferentiation extends to the auditory cortex. Inspired by previous animal work, we also investigated whether individual differences in GABA are associated with individual differences in neural distinctiveness in humans. 20 healthy young adults (ages 18-29) and 23 healthy older adults (over 65) completed a functional magnetic resonance imaging (fMRI) scan, during which neural activity was estimated while they listened to music and foreign speech. GABA levels in the auditory, ventrovisual and sensorimotor cortex were estimated in the same individuals in a separate magnetic resonance spectroscopy (MRS) scan. Relative to the younger adults, the older adults exhibited both (1) less distinct activation patterns for music vs. speech stimuli and (2) lower GABA levels in the auditory cortex. Also, individual differences in auditory GABA levels (but not ventrovisual or sensorimotor GABA levels) were associated with individual differences in neural distinctiveness in the auditory cortex in the older adults. These results demonstrate that age-related neural dedifferentiation extends to the auditory cortex and suggest that declining GABA levels may play a role in neural dedifferentiation in older adults.
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Affiliation(s)
- Poortata Lalwani
- Department of Psychology, University of Michigan, Ann Arbor, MI, 48109, USA.
| | - Holly Gagnon
- Department of Psychology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Kaitlin Cassady
- Department of Psychology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Molly Simmonite
- Department of Psychology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Scott Peltier
- Department of Bioengineering, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Rachael D Seidler
- Department of Applied Physiology & Kinesiology, University of Florida, Gainesville, FL, 32611, USA
| | - Stephan F Taylor
- Department of Psychology, University of Michigan, Ann Arbor, MI, 48109, USA; Department of Psychiatry, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Daniel H Weissman
- Department of Psychology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Thad A Polk
- Department of Psychology, University of Michigan, Ann Arbor, MI, 48109, USA
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91
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Koen JD, Rugg MD. Neural Dedifferentiation in the Aging Brain. Trends Cogn Sci 2019; 23:547-559. [PMID: 31174975 PMCID: PMC6635135 DOI: 10.1016/j.tics.2019.04.012] [Citation(s) in RCA: 164] [Impact Index Per Article: 32.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 04/22/2019] [Accepted: 04/24/2019] [Indexed: 11/17/2022]
Abstract
Many cognitive abilities decline with age even in the absence of detectable pathology. Recent evidence indicates that age-related neural dedifferentiation, operationalized in terms of neural selectivity, may contribute to this decline. We review here work exploring the relationship between neural dedifferentiation, cognition, and age. Compelling evidence for age effects on neural selectivity comes from both non-human animal and human research. However, current data suggest that age does not moderate the observed relationships between neural dedifferentiation and cognitive performance. We propose that functionally significant variance in measures of neural dedifferentiation reflects both age-dependent and age-independent factors. We further propose that the effects of age on neural dedifferentiation do not exclusively reflect detrimental consequences of aging.
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Affiliation(s)
- Joshua D Koen
- Department of Psychology, University of Notre Dame, Notre Dame, IN 46556, USA.
| | - Michael D Rugg
- Center for Vital Longevity, School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, TX 75235, USA
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92
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Respino M, Jaywant A, Kuceyeski A, Victoria LW, Hoptman MJ, Scult MA, Sankin L, Pimontel M, Liston C, Belvederi Murri M, Alexopoulos GS, Gunning FM. The impact of white matter hyperintensities on the structural connectome in late-life depression: Relationship to executive functions. Neuroimage Clin 2019; 23:101852. [PMID: 31077981 PMCID: PMC6514361 DOI: 10.1016/j.nicl.2019.101852] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Revised: 04/06/2019] [Accepted: 05/02/2019] [Indexed: 12/28/2022]
Abstract
BACKGROUND White matter hyperintensities (WMH) represent ischemic white matter damage in late-life depression (LLD) and are associated with cognitive control dysfunction. Understanding the impact of WMH on the structural connectivity of gray matter and the cognitive control correlates of WMH-related structural dysconnectivity can provide insight into the pathophysiology of LLD. METHODS We compared WMH burden and performance on clinical measures of cognitive control in patients with LLD (N = 44) and a control group of non-depressed older adults (N = 59). We used the Network Modification (NeMo) Tool to investigate the impact of WMH on structural dysconnectivity in specific gray matter regions, and how such connectivity was related to cognitive control functions. RESULTS Compared to the control group, LLD participants had greater WMH burden, poorer performance on Trail Making Test (TMT) A & B, and greater self-reported dysexecutive behavior on the Frosntal Systems Behavior Scale-Executive Function subscale (FrSBe-EF). Within the LLD group, disrupted connectivity in the left supramarginal gyrus, paracentral lobule, thalamus, and pallidum was associated with psychomotor slowing (TMT-A). Altered connectivity in the left supramarginal gyrus, paracentral lobule, precentral gyrus, postcentral gyrus, thalamus, and pallidum was associated with poor attentional set-shifting (TMT-B). A follow-up analysis that isolated set-shifting ability (TMT-B/A ratio) confirmed the association with dysconnectivity in the bilateral paracentral lobule, right thalamus, left precentral gyrus, postcentral gyrus, and pallidum; additionally, it revealed associations with dysconnectivity in the right posterior cingulate, and left anterior cingulate, middle frontal cortex, and putamen. CONCLUSIONS In LLD, WMH are associated with region-specific disruptions in cortical and subcortical gray matter areas involved in attentional aspects of cognitive control systems and sensorimotor processing, which in turn are associated with slower processing speed, and reduced attentional set-shifting. CLINICAL TRIALS REGISTRATION https://clinicaltrials.gov/ct2/show/NCT01728194.
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Affiliation(s)
- Matteo Respino
- Department of Psychiatry, Weill Cornell Medicine, 525 E 68(th) St, New York, NY 10065, USA; Weill Cornell Institute of Geriatric Psychiatry, 21 Bloomingdale Road, White Plains, NY 10605, USA
| | - Abhishek Jaywant
- Department of Psychiatry, Weill Cornell Medicine, 525 E 68(th) St, New York, NY 10065, USA; Department of Rehabilitation Medicine, Weill Cornell Medicine, 525 E 68(th) St, New York, NY 10065, USA
| | - Amy Kuceyeski
- Department of Radiology, Weill Cornell Medicine, 525 E 68(th) St, New York, NY 10065, USA
| | - Lindsay W Victoria
- Department of Psychiatry, Weill Cornell Medicine, 525 E 68(th) St, New York, NY 10065, USA; Weill Cornell Institute of Geriatric Psychiatry, 21 Bloomingdale Road, White Plains, NY 10605, USA
| | - Matthew J Hoptman
- Clinical Research, Nathan Kline Institute, 140 Old Orangeburg Road, Orangeburg, NY 10962, USA; Department of Psychiatry, NYU School of Medicine, 550 First Avenue, New York, NY 10016, USA
| | - Matthew A Scult
- Department of Psychiatry, Weill Cornell Medicine, 525 E 68(th) St, New York, NY 10065, USA
| | - Lindsey Sankin
- Department of Psychiatry, Weill Cornell Medicine, 525 E 68(th) St, New York, NY 10065, USA
| | - Monique Pimontel
- Department of Psychiatry, Weill Cornell Medicine, 525 E 68(th) St, New York, NY 10065, USA
| | - Conor Liston
- Department of Psychiatry, Weill Cornell Medicine, 525 E 68(th) St, New York, NY 10065, USA; Feil Family Brain Mind Research Institute, Weill Cornell Medicine, 413 East 69(th) St, New York, NY 10021, USA
| | - Martino Belvederi Murri
- Department of Neuroscience, Ophthalmology, Genetics and Child-Maternal Science, University of Genoa, Corso Italia 22, 16145 Genova, Italy
| | - George S Alexopoulos
- Department of Psychiatry, Weill Cornell Medicine, 525 E 68(th) St, New York, NY 10065, USA; Weill Cornell Institute of Geriatric Psychiatry, 21 Bloomingdale Road, White Plains, NY 10605, USA
| | - Faith M Gunning
- Department of Psychiatry, Weill Cornell Medicine, 525 E 68(th) St, New York, NY 10065, USA; Weill Cornell Institute of Geriatric Psychiatry, 21 Bloomingdale Road, White Plains, NY 10605, USA.
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93
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Ruitenberg MFL, Cassady KE. Commentary: Age Differentiation within Gray Matter, White Matter, and between Memory and White Matter in an Adult Life Span Cohort. Front Aging Neurosci 2019; 11:93. [PMID: 31057393 PMCID: PMC6482270 DOI: 10.3389/fnagi.2019.00093] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 04/04/2019] [Indexed: 11/23/2022] Open
Affiliation(s)
- Marit F. L. Ruitenberg
- Department of Experimental Psychology, Ghent University, Ghent, Belgium
- *Correspondence: Marit F. L. Ruitenberg
| | - Kaitlin E. Cassady
- Department of Psychology, University of Michigan, Ann Arbor, MI, United States
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