The neural mechanisms underlying the promotion of motor learning by acute exercise

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A growing body of literature demonstrates that acute aerobic exercise (AEX) promotes motor skill learning and alters neuroplasticity-like mechanisms in the motor cortex. It is thought that these changes in neuroplasticity underlie the facilitation of skill acquisition and motor learning, yet no data links the modulation of brain and behaviour due to `priming' AEX. As a consequence, knowledge of the neural mechanisms supporting the effects of AEX is incomplete. The current lack of knowledge stems in part from a notable absence of investigation into: i) the key brain regions and circuits supporting the AEX-induced effects to neuroplasticity, and ii) the influence of skill level on motor learning tasks `primed' by AEX. These fundamental questions motivate the proposed research program. Recent advances in technology and research have afforded the potential to measure distinct cortical interneurons in the brain, and specifically within the motor cortex. Two distinct sets of cortical interneurons can be assessed using transcranial magnetic stimulation (TMS). My recent work, along with others, demonstrates that these interneuron populations respond uniquely to motor behaviour and repetitive TMS protocols designed to alter cortical excitability. Accumulating evidence suggests that AEX impacts motor cortex excitability, yet taken together the evidence is lacking and contradictory. My work, along with others, is suggestive that AEX may uniquely modulate motor cortical interneurons, yet no work has directly tested this question. My recent work suggests that prefrontal, parietal and cerebellar circuits contribute to motor cortex excitability change following AEX. This is bolstered by my work demonstrating AEX simultaneously improves reaching accuracy and accelerates reaction time at a skilled visuomotor task, suggesting an interactive enhancement of cognitive strategy and sensorimotor execution. Since the early stages of motor skill acquisition involves increased activity in frontal, parietal and cerebellar regions, it follows that AEX would facilitate these circuits to promote motor learning. Therefore, the current proposal will investigate the associations between: motor, prefrontal, parietal and cerebellar circuit modulation with the influence of skill in motor learning tasks `primed' by AEX. This research program will be the first to uncover the critical brain regions and circuits impacted by AEX to support enhanced skill acquisition and motor learning. My proposed work represents a unique opportunity to develop our knowledge of AEX-induced neuroplasticity by capitalizing on advanced techniques of brain stimulation. It is anticipated that the results of this research program will contribute to novel and improved understanding of the neural and behavioural mechanisms underlying the impact of AEX on motor learning.