title: Acute aerobic exercise modulates primary motor cortex inhibition.
abstract: Aerobic exercise can enhance neuroplasticity although presently the neural mechanisms underpinning these benefits remain unclear. One possible mechanism is through effects on primary motor cortex (M1) function via down-regulation of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA). The aim of the present study was to examine how corticomotor excitability (CME) and M1 intracortical inhibition are modulated in response to a single bout of moderate intensity aerobic exercise. Ten healthy right-handed adults were participants. Single- and paired-pulse transcranial magnetic stimulation was applied over left M1 to obtain motor-evoked potentials in the right flexor pollicis brevis. We examined CME, cortical silent period (SP) duration, short- and long-interval intracortical inhibition (SICI, LICI), and late cortical disinhibition (LCD), before and after acute aerobic exercise (exercise session) or an equivalent duration without exercise (control session). Aerobic exercise was performed on a cycle ergometer for 30 min at a workload equivalent to 60 % of maximal cardiorespiratory fitness (VO2peak; heart rate reserve = 75 ± 3 %, perceived exertion = 13.5 ± 0.7). LICI was reduced at 10 (52 ± 17 %, P = 0.03) and 20 min (27 ± 8 %, P = 0.03) post-exercise compared to baseline (13 ± 4 %). No significant changes in CME, SP duration, SICI or LCD were observed. The present study shows that GABAB-mediated intracortical inhibition may be down-regulated after acute aerobic exercise. The potential effects this may have on M1 plasticity remain to be determined.
authors: Movement Neuroscience Laboratory, The University of Auckland, Auckland, New Zealand.|Centre for Brain Research, The University of Auckland, Auckland, New Zealand.
authors: Ronan A
authors: RA
authors: Mooney
authors: School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, VIC, Australia.|Centre for Brain Research, The University of Auckland, Auckland, New Zealand.
authors: James P
authors: JP
authors: Coxon
authors: Movement Neuroscience Laboratory, The University of Auckland, Auckland, New Zealand.|Centre for Brain Research, The University of Auckland, Auckland, New Zealand.
authors: John
authors: J
authors: Cirillo
authors: Movement Neuroscience Laboratory, The University of Auckland, Auckland, New Zealand.|Centre for Brain Research, The University of Auckland, Auckland, New Zealand.
authors: Helen
authors: H
authors: Glenny
authors: Exercise Neurometabolism Laboratory, Department of Exercise Sciences, The University of Auckland, Auckland, New Zealand.|Centre for Brain Research, The University of Auckland, Auckland, New Zealand.
authors: Nicholas
authors: N
authors: Gant
authors: Movement Neuroscience Laboratory, The University of Auckland, Auckland, New Zealand. w.byblow@auckland.ac.nz.|Centre for Brain Research, The University of Auckland, Auckland, New Zealand. w.byblow@auckland.ac.nz.
authors: Winston D
authors: WD
authors: Byblow
mesh_terms: D000293:Adolescent; D000328:Adult; D004576:Electromyography; D019054:Evoked Potentials, Motor / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D005260:Female; D006225:Hand / Q000294:innervation; D006801:Humans; D008297:Male; D009044:Motor Cortex / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology; D009433:Neural Inhibition / Q000502:physiology*; D018709:Statistics, Nonparametric; D050781:Transcranial Magnetic Stimulation; D055815:Young Adult
keywords: Aerobic exercise; Intracortical inhibition; Motor cortex; Transcranial magnetic stimulation