An acute bout of exercise modulates both intracortical and interhemispheric excitability
Bibliographic record
Abstract
Primary motor cortex (M1) excitability is modulated following a single session of cycling exercise. Specifically, short-interval intracortical inhibition and intracortical facilitation are altered following a session of cycling, suggesting that exercise affects the excitability of varied cortical circuits. Yet we do not know whether a session of exercise also impacts the excitability of interhemispheric circuits between, and other intracortical circuits within, M1. Here we present two experiments designed to address this gap in knowledge. In experiment 1, single and paired pulse transcranial magnetic stimulation (TMS) were used to measure intracortical circuits including, short-interval intracortical facilitation (SICF) tested at 1.1, 1.5, 2.7, 3.1 and 4.5 ms interstimulus intervals (ISIs), contralateral silent period (CSP) and interhemispheric interactions by measuring transcallosal inhibition (TCI) recorded from the abductor pollicus brevis muscles. All circuits were assessed bilaterally pre and two time points post (immediately, 30 min) moderate intensity lower limb cycling. SICF was enhanced in the left hemisphere after exercise at the 1.5 ms ISI. Also, CSP was shortened and TCI decreased bilaterally after exercise. In Experiment 2, corticospinal and spinal excitability were tested before and after exercise to investigate the locus of the effects found in Experiment 1. Exercise did not impact motor-evoked potential recruitment curves, Hoffman reflex or V-wave amplitudes. These results suggest that a session of exercise decreases intracortical and interhemispheric inhibition and increases facilitation in multiple circuits within M1, without concurrently altering spinal excitability. These findings have implications for developing exercise strategies designed to potentiate M1 plasticity and skill learning in healthy and clinical populations.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.002 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".