Exercise-induced Alteration in Brain Activity during Motor Performance under Cognitive Stress

Abstract

Fine motor tasks are rarely completed in isolation. Previous research shows that a concurrent cognitive task degrades fine motor task performance by decreasing neural oscillations between the brain and muscles. However, the effect of high-intensity physical exertion on motor performance is not known. The purpose of this study is to examine the changes in beta-band (15-30 Hz) neural oscillations (coherence and power) after intense exercise. Nineteen healthy, right-handed, young adults were asked to complete a force matching task with their right index finger either independently (single task) or concurrently with a cognitive task (dual task). There were 3 time blocks consisting of 10 trials each, Between blocks 1 and 2, the subjects in the experimental group performed active leg exercise while those in the control groups had their legs moved passively. During each trial, EMG at the first dorsal interosseous (FDI) muscle and EEG of the primary motor cortex were recorded as well as other sensors such as force production, blood pressure, and perceived exertion, Peak beta-band corticomuscular coherence frequency was significantly greater (p=0.04) during the dual task trials, Beta-band coherence and EEG power decreased, on average, during the dual-task trials after active exercise but this trend was not significant. There was no significant effect of time, task or group on EEG power or peak beta-band coherence, There is a significant negative correlation (r=-0,31, p=0.021) between peak beta-band coherence and the coefficient of variation of EMG during dual task trials. These findings imply that the effect of exercise on fine motor performance and neural oscillations under stress may depend on the type of motor task.