Aerobic exercise and action observation priming modulate functional connectivity

Abstract

Aerobic exercise and action observation are two clinic-ready modes of neural priming that have the potential to enhance subsequent motor learning. Prior work using transcranial magnetic stimulation to assess priming effects have shown changes in corticospinal excitability involving intra- and interhemispheric circuitry. The objective of this study was to determine outcomes exclusive to priming- how aerobic exercise and action observation priming influence functional connectivity within a sensorimotor neural network using electroencephalography. We hypothesized that both action observation and aerobic exercise priming would alter resting-state coherence measures between dominant primary motor cortex and motor-related areas in alpha (7-12 Hz) and beta (13-30 Hz) frequency bands with effects most apparent in the high beta (20-30 Hz) band. Nine unimpaired individuals (24.8 ± 3 years) completed a repeated-measures cross-over study where they received a single five-minute bout of action observation or moderate-intensity aerobic exercise priming in random order with a one-week washout period. Serial resting-state electroencephalography recordings acquired from 0 to 30 minutes following aerobic and action observation priming revealed increased alpha and beta coherence between leads overlying dominant primary motor cortex and supplementary motor area relative to pre- and immediate post-priming timepoints. Aerobic exercise priming also resulted in enhanced high beta coherence between leads overlying dominant primary motor and parietal cortices. These findings indicate that a brief bout of aerobic- or action observation-based priming modulates functional connectivity with effects most pronounced with aerobic priming. The gradual increases in coherence observed over a 10 to 30-minute post-priming window may guide the pairing of aerobic- or action observation-based priming with subsequent training to optimize learning-related outcomes.

Fig 1. Experiment and study design.

Participants completed one baseline visit and two priming visits (grey boxes) separated by a one-week washout period. Priming order was randomized to either aerobic exercise priming first and action observation priming second (dotted arrows) or action observation priming first followed by aerobic exercise priming a week later (solid arrows). During each priming visit, participants completed five three-minute resting-state electroencephalography recordings before, after, and at 10, 20, and 30 minutes following a 5-minute bout of priming.

Fig 2. EEG coherence pre/post priming.

Aerobic exercise (A) and action observation (AO) priming resulted in enhanced EEG coherence in alpha (7–12 Hz, top), low beta (13–19 Hz, middle), and high beta (20–30 Hz, bottom) frequency bands most pronounced at 10, 20, and 30 minutes post-priming (Post10, Post20, and Post30). White leads represent the coherence seed region overlying left primary motor cortex. Black leads denote right primary motor cortex, grey leads denote left parietal cortex, green leads denote dorsal premotor cortex, and magenta leads denote supplementary motor area.

Fig 3. Coherence in leads overlying left primary motor (lM1) cortex and supplementary motor area (SMA).

Significant increases in alpha, low beta, and high beta lM1-SMA coherence occurred after aerobic (A) and action observation (B) priming. Individual participant data points illustrated along with group averages and standard deviations. ‡ indicates significant increase from pre timepoint. * indicates significant increase from post timepoint.

Fig 4. Coherence in leads overlying left primary motor (lM1) and left parietal (lPr) cortices.

Increases in high beta lM1-lPr coherence occurred after aerobic priming (A). ‡ indicates significant change from pre timepoint. * indicates significant increase from post timepoint.

Fig 5. Coherence in leads overlying left primary motor (lM1) and right primary motor (rM1) cortices.

Increases in high beta lM1-rM1 coherence occurred following aerobic priming (A). ‡ indicates significant increase from pre timepoint. * indicates significant increase from post timepoint.

Fig 6. Coherence in leads overlying left primary motor (lM1) and left dorsal premotor (lPMd) cortices.

Aerobic (A) and action observation (B) priming did not result in any significant change in alpha, low beta, or high beta lM1-lPMd coherence.