Investigating cortical buffering effects of acute exercise: A cTBS study targeting the left dorsolateral prefrontal cortex

Abstract

Objective: The beneficial effects of both single-session bouts of aerobic exercise and therapeutic exercise interventions on the cortical regions associated with executive functions (i.e., prefrontal cortex (PFC)) and memory (i.e., the hippocampus) have been well documented. However, it remains unclear whether aerobic exercise can be used to offset temporary fluctuations in cortical activity. The current study sought to determine whether a single session of moderate intensity aerobic exercise can offset the attenuating effects of continuous theta burst stimulation (cTBS) targeting the dorsolateral prefrontal cortex (dlPFC).

Methods: Twenty-two healthy right-handed participants between 18-30 years completed a 20 minute session of light intensity (10% heart rate reserve (HRR)) and moderate intensity (50% HRR) exercise in a counterbalanced order. Following each exercise session, participants received active cTBS to the left dorsolateral prefrontal cortex (dlPFC). Changes in executive functions were quantified using a flanker paradigm employed at baseline, pre-cTBS and post-cTBS time points. In addition, EEG methodologies were used to measure changes in inhibitory control specific event-related potential components (i.e., P3 and N2) in response to the flanker task.

Results: Behavioural results from the Flanker task revealed a non-significant effect of exercise on cTBS in both light and moderate intensity conditions (F(1,21)=0.219, p= 0.804). Similarly, EEG data from the P3 (F(2,40)= .789, p=.461) and N2 (F(2,40)= 1.819, p=.175) ERP components revealed a non-significant effect of amplitude across time and condition. P3 latency data revealed a significant effect of time in the light intensity condition (F(2,40)=4.313, p=.020), such that latency was faster following cTBS. Similarly, latency data within the N2 ERP component revealed a significant effect of time on congruent trials (F(2,40)=17.206, p=0.00) in the light intensity condition; N2 latency was faster following cTBS on congruent trials.

Conclusion: The current study revealed that light and moderate intensity exercise may provide a buffer to cTBS- induced attenuation of the dlPFC. This study provides empirical and theoretical implications on the potential for exercise to promote cognitive control.