Uncovering the role of the human primary motor cortex in cardiovascular control during exercise: A transcranial magnetic stimulation investigation

Abstract

The possible implication of the human primary motor cortex (M1) in the control of the cardiovascular autonomic system during rest and exercise was assessed in normotensive participants. Participants underwent three conditions using transcranial magnetic stimulation; Sham (control), continuous theta burst stimulation (cTBS) and intermittent theta burst stimulation (iTBS). Heart rate (HR), arterial blood pressure (ABP) and muscle sympathetic nerve activity (MSNA) were recorded post-stimulation during baseline rest, a 2-minute isometric handgrip exercise and a post-exercise ischemia period where blood flow to the previously active forearm and hand is occluded. Results showed that iTBS significantly facilitated M1 compared to sham and baseline (p ≤ 0.05), but cTBS failed to cause inhibition as expected. However, significant differences between conditions were still found during resting measures. The changes we observed in cardiac autonomic measures suggest M1 may be implicated in the control of the cardiovascular system.