Exercise and microstructural changes in the motor cortex of older adults

Area of Science:

• Neuroscience
• Gerontology
• Exercise Physiology

Background:

• Age-related brain volume loss is a known phenomenon.
• Previous research indicates exercise can mitigate these volume decreases.
• The impact of exercise on cortical microstructure in aging remains less understood.

Purpose of the Study:

• To investigate if regular exercise can preserve or improve cortical microstructure in healthy older adults.
• To examine the relationship between exercise, cortical microstructural changes, and aerobic fitness.

Main Methods:

• A 12-week randomized controlled trial involving 47 healthy older adults (65-90 years).
• Participants were assigned to either a supervised stationary cycling program (3 times/week) or a control group maintaining their usual routine.
• Quantitative longitudinal relaxation rate (R1) magnetic resonance imaging (MRI) was used to assess cortical myelin density at baseline and post-intervention.

Main Results:

• The exercise group showed a significant increase in R1 change (ΔR1) in the primary motor cortex region related to leg muscles compared to the control group (p=0.04).
• This microstructural change correlated with improvements in aerobic fitness, specifically oxygen consumption at the first ventilatory threshold (VT1) (p=0.04).
• Exploratory analysis indicated the correlation was primarily localized to the leg representation area within the motor cortex.

Conclusions:

• Regular aerobic exercise may help counteract age-related microstructural declines in the human cortex.
• Exercise-induced improvements in cortical myelin density are linked to enhanced aerobic capacity in older adults.
• Targeted exercise interventions could be a strategy to maintain brain health during aging.