Aging and Cortical Excitability

Study Overview
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Brief Summary
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The objective of the current proposal is to identify 1) how aging-related changes in GABAergic cortical inhibition affect motor performance, and 2) how aerobic exercise may improve inhibitory function and facilitate motor learning.

Detailed Description
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The current proposal seeks quantify neural inhibition using magnetic resonance spectroscopy (MRS) and transcranial magnetic stimulation (TMS) in older Veterans to identify how each measures contributes to aging-related changes in motor performance. Currently, over 56% (11.8 million) of Veterans are over age 60. Recent research has shown that aging is associated with decreased cortical inhibition and impaired hand motor function. However, this loss of inhibition is not an inescapable consequence of aging. The investigators' previous work that healthy older adults who engage in regular physical activity show increased cortical inhibition and improved dexterity as compared to their sedentary age cohort. This indicates that aerobic training may reverse aging related changes in cortical inhibition and alteration of tonic levels of cortical excitability can have a powerful impact on motor performance in the aging brain. In the current proposal, the investigators will enroll older adults to assess how different measurements (TMS and MRS) of the dominant inhibitory neurotransmitter in the brain - GABA differ in relation to motor control. During the MRS scan, participants will perform a motor learning task to assess change in GABA level throughout the acquisition session. These data will be compared with measures of cortical inhibition using TMS to quantify neurotransmitter receptor activity with respect to aging-related changes in motor performance. The investigators will also be comparing the effects of an aerobic exercise intervention as compared to a contact matched stretching control. The investigators believe this project is the first inquiry of its kind and will have an important impact in the understanding of aging-related neurophysiological changes in the brain and how it can remediate associated behavioral declines.

Official Title
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Effects of Aging on Cortical Excitability During Motor Learning

Conditions
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Aging

Intervention / Treatment
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* Behavioral: Aerobic Exercise
* Behavioral: Stretching and Balance Training


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: living persons aged 50-85 Exclusion Criteria: unmanaged diabetes participants completing vigorous exercise per week participants whose profession requires vigorous physical labor contraindication to magnetic resonance imaging

Ages Eligible for Study
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Minimum Age: 50 Years
Maximum Age: 85 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Two group parallel design
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Aerobic Exercise<br>Participants will engage in an aerobic exercise program meeting thrice weekly for a period of 12 weeks. | Behavioral: Aerobic Exercise<br>* Participants will engage in an aerobic exercise program meeting thrice weekly for a period of 12 weeks.<br>* Other names: AE; Exercise;|
| Active Comparator: Stretching and Balance Training<br>Participants will engage in a balance and stretching comparator condition meeting thrice weekly for 12 weeks. | Behavioral: Stretching and Balance Training<br>* Participants will engage in a balance and stretching comparator condition meeting thrice weekly for 12 weeks.<br>* Other names: BAL; Balance;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Magnetic Resonance Spectroscopy | Measuring changes in dynamic magnetic resonance spectroscopy of primary motor cortex during motor learning. | Pre/Post 12 week intervention | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Transcranial Magnetic Stimulation | Measure changes in TMS measures of cortical excitability pre/post intervention. | Pre/Post 12 week intervention | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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aging