Acute Exercise Protects Newly Formed Motor Memories Against rTMS-induced Interference Targeting Primary Motor Cortex. (1st June 2020) - Beck, Mikkel Malling
Highlights: We tested the effects of a single bout of exercise or rest on rTMS-induced interference with motor memory consolidation. rTMS targeting the primary motor cortex (M1) impeded offline performance changes for the resting group compared to sham. A single bout of exercise counteracted the negative effects of rTMS on offline performance changes. Acute exercise protects against retrograde interference from rTMS in a network comprising M1 and the corticospinal system. Our results suggest that M1 and the corticospinal system mediate the effects of exercise on motor memory consolidation. Abstract: Acute cardiovascular exercise can promote motor memory consolidation following motor practice, and thus long-term retention, but the underlying mechanisms remain sparsely elucidated. Here we test the hypothesis that the positive behavioral effects of acute exercise involve the primary motor cortex and the corticospinal pathway by interfering with motor memory consolidation using non-invasive, low frequency, repetitive transcranial magnetic stimulation (rTMS). Forty-eight able-bodied, young adult male participants (mean age = 24.8 y/o) practiced a visuomotor accuracy task demanding precise and fast pinch force control. Following motor practice, participants either rested or exercised (20 min total: 3 × 3 min at 90% VO2peak ) before receiving either sham rTMS or supra-threshold rTMS (115% RMT, 1 Hz) targeting the hand area of the contralateral primary motor cortex for 20 min. Retention was evaluated 24 h following motor practice, and motor memory consolidation was operationalized as overnight changes in motor performance. Low-frequency rTMS resulted in off-line decrements in motor performance compared to sham rTMS, but these were counteracted by a preceding bout of intense exercise. These findings demonstrate that a single session of exercise promotes early motor memory stabilization and protects the primary motor cortex and the corticospinal system against interference.