The beneficial effects of exercise on brain health and cognitive function have been well established. However, the effects of acute exercise on cortical activation during the performance of a motor task are less well known. Understanding these effects have implications for acute interventions on cognitive health and cognitive performance.
PURPOSE: To examine the blood oxygen level dependent (BOLD) signal, measured by fMRI, in the motor and/or supplementary cortices in response to a finger tapping task performed after acute aerobic exercise, and to determine if these effects are exercise intensity-related.
METHODS: On two separate visits, 14 healthy young (24.1+4.1 yrs) subjects completed two baseline fMRI scans during which a simple motor task was performed. The task was a block designed flashing green and black checkerboard at a frequency of 3 Hz, alternating between 30 second intervals of flashing (stimulus) and black screen (control). Subjects had to tap their right index finger to match the flashing rate. Following the baseline scan, subjects completed a 30-minute exercise condition of either low (LI) (30-40% HRR) or moderate (MI) (50-60% HRR) intensity exercise (counterbalanced). Immediately following each exercise session, subjects completed the same fMRI task. Changes in brain activation during the task reflected the difference between the stimulus and control blocks and were quantified by the BOLD signal.
RESULTS: Following MI, activation in the left anterior cingulate was decreased (p<0.002) and activation was increased in the left middle and superior frontal gyri (p<0.005). Following LI, activation in the left-precentral gyrus increased (p<0.005). Only one brain region changed significantly following both conditions, the left middle frontal gyrus (p<0.005); a decrease in BOLD signal following LI, and an increase in BOLD signal following MI.
CONCLUSION: Acute exercise results in changes in neural activation during the performance of a simple motor task, and these changes are intensity-dependent. The brain regions affected by exercise may indicate a positive influence by acute exercise on attention, awareness, motor readiness, and motor performance. These findings suggest LI exercise may be optimal to enhance brain activation during simple motor function.