Examining Interhemispheric Inhibition During the Simultaneous Combination of Multiple Action States
Bibliographic record
Abstract
Unilateral movement relies on an inhibitory connection between the motor cortices of the brain, referred to as interhemispheric inhibition (IHI). IHI is well established during the execution of unilateral actions. However, it is unknown if and how IHI is moderated when physical execution (PE) is combined with either simultaneous action observation (AO) or motor imagery (MI), informing the neurophysiology of these covert 'action states'. Participants (N=24) performed unilateral concentric wrist contractions (50% MVC) under three conditions: PE, PE+AO, and PE+MI. To index IHI, we induced an ipsilateral silent period (iSP) during each contraction via transcranial magnetic stimulation (TMS) over the ipsilateral motor cortex and with electromyography recorded from extensor carpi radialis. If MI or AO require less lateralization (i.e., bilateral recruitment of the motor cortices), combined conditions should result in a shorter iSP vs. PE. Relative to the mean iSP for PE (30.5, SD=24ms), iSP was reduced only during PE+AO (21.9, SD=17ms, d=.36), not PE+MI (29.0, SD=28ms, d=.06). These data suggest that PE+AO promotes bilateral recruitment (greater 'interhemispheric cooperation'). A preliminary analysis (N=17) of motor evoked potential (MEP) amplitude obtained from electromyography recorded over the ipsilateral hemisphere suggests corticospinal excitability was consistent across the task. Specifically, relative to PE (1535, SD=1370uV), MEP amplitude did not change during PE+MI (1456, SD=313uV, d=.06) nor PE+AO (1492, SD=1216uV, d=.03). Overall, this work expands knowledge of neural mechanisms sub-serving multiple action states and underlying neurophysiology.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 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 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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 source (direct Gemma or distilled Codex), 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".