scholarly journals Does Hemispheric Asymmetry Reduction in Older Adults (HAROLD) in motor cortex reflect compensation?

2021 ◽  
pp. JN-RM-1111-21
Author(s):  
Ethan Knights ◽  
Alexa Morcom ◽  
Richard N. Henson
Keyword(s):  
Older Adults ◽  
Motor Cortex ◽  
Hemispheric Asymmetry

scholarly journals Does Hemispheric Asymmetry Reduction in Older Adults (HAROLD) in motor cortex reflect compensation?

2021 ◽  
Author(s):  
Ethan Knights ◽  
Alexa Morcom ◽  
Richard N Henson ◽  
Keyword(s):  
Older Adults ◽  
Motor Cortex ◽  
Hemispheric Asymmetry ◽  
Activity Patterns ◽  
Compensatory Mechanism ◽  
Adult Lifespan ◽  
Additional Information ◽  
Age Related ◽  
Alternative Hypotheses ◽  
Neural Efficiency

Older adults tend to display greater brain activation in the non-dominant hemisphere during even basic sensorimotor responses. It is debated whether this Hemispheric Asymmetry Reduction in Older Adults (HAROLD) reflects a compensatory mechanism. Across two independent fMRI experiments involving an adult-lifespan human sample (N = 586 and N = 81; approximately half female) who performed right hand finger responses, we distinguished between these hypotheses using behavioural and multivariate Bayes (MVB) decoding approaches. Standard univariate analyses replicated a HAROLD pattern in motor cortex, but in- and out-of-scanner behavioural results both demonstrated evidence against a compensatory relationship, in that reaction time measures of task performance in older adults did not relate to ipsilateral motor activity. Likewise, MVB showed that this increased ipsilateral activity in older adults did not carry additional information, and if anything, combining ipsilateral with contralateral activity patterns reduced action decoding in older adults (at least in Experiment 1). These results contradict the hypothesis that HAROLD is compensatory, and instead suggest that the age-related, ipsilateral hyper-activation is non-specific, in line with alternative hypotheses about age-related reductions in neural efficiency/differentiation or inter-hemispheric inhibition.

Reduced dorsal premotor cortex and primary motor cortex connectivity in older adults

2015 ◽  
Vol 36 (1) ◽  
pp. 301-303 ◽  
Author(s):  
Zhen Ni ◽  
Reina Isayama ◽  
Gabriel Castillo ◽  
Carolyn Gunraj ◽  
Utpal Saha ◽  
...  
Keyword(s):  
Older Adults ◽  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Premotor Cortex ◽  
Dorsal Premotor Cortex

Exercise and microstructural changes in the motor cortex of older adults

2019 ◽  
Vol 51 (7) ◽  
pp. 1711-1722 ◽  
Author(s):  
Christopher D. Rowley ◽  
Nicholas A. Bock ◽  
Ralf Deichmann ◽  
Tobias Engeroff ◽  
Elke Hattingen ◽  
...  
Keyword(s):  
Older Adults ◽  
Motor Cortex ◽  
Microstructural Changes

scholarly journals Anticipatory postural adjustments and spatial organization of motor cortex: evidence of adaptive compensations in healthy older adults

2018 ◽  
Vol 120 (6) ◽  
pp. 2796-2805 ◽  
Author(s):  
Jo Armour Smith ◽  
Beth E. Fisher
Keyword(s):  
Older Adults ◽  
Motor Cortex ◽  
Spatial Organization ◽  
Gluteus Medius ◽  
Anticipatory Postural Adjustments ◽  
Temporal Organization ◽  
Postural Adjustments ◽  
Healthy Older Adults ◽  
History Of ◽  
External Oblique

During anticipated postural perturbations induced by limb movement, the central nervous system generates anticipatory postural adjustments (APAs) in the trunk and hip musculature to minimize disturbances to equilibrium. Age-related changes in functional organization of the nervous system may contribute to changes in APAs in healthy older adults. Here we examined if altered APAs of trunk/hip musculature in older adults are accompanied by changes in the representation of these muscles in motor cortex. Twelve healthy older adults, 5 with a history of falls and 7 nonfallers, were compared with 13 young adults. APAs were assessed during a mediolateral arm raise task in standing. Temporal organization of postural adjustments was quantified as latency of APAs in the contralateral external oblique, lumbar paraspinals, and gluteus medius relative to activation of the deltoid. Spatial organization was quantified as extent of synergistic coactivation between muscles. Volume and location of the muscle representations in motor cortex were mapped using transcranial magnetic stimulation. We found that older adults demonstrated significantly delayed APAs in the gluteus medius muscle. Spatial organization of the three muscles in motor cortex differed between groups, with the older adults demonstrating more lateral external oblique representation than the other two muscles. Separate comparisons of the faller and nonfaller subgroups with young adults indicated that nonfallers had the greatest delay in gluteus medius APAs and a reduced distance between the representational areas of the lumbar paraspinals and gluteus medius. This study indicates that altered spatial organization of motor cortex accompanies altered temporal organization of APA synergies in older adults. NEW & NOTEWORTHY Anticipatory postural adjustments are a critical component of postural control. Here we demonstrate that, in healthy older adults with and without a history of falls, delayed anticipatory postural adjustments in the hip musculature during mediolateral perturbations are accompanied by altered organization of trunk/hip muscle representation in motor cortex. The largest adaptations are evident in older adults with no history of falls.

P 171. Bihemispheric motor cortex stimulation in older adults induces modulations of resting state and task-related activity

2013 ◽  
Vol 124 (10) ◽  
pp. e146 ◽  
Author(s):  
R. Lindenberg ◽  
L. Nachtigall ◽  
M. Meinzer ◽  
M.M. Sieg ◽  
A. Flöel
Keyword(s):  
Older Adults ◽  
Motor Cortex ◽  
Resting State ◽  
Motor Cortex Stimulation ◽  
Related Activity ◽  
And Task
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