Motor learning induces time‐dependent plasticity that is observable at the spinal cord level
Bibliographic record
Abstract
KEY POINTS: The spinal cord is an important contributor to motor learning It remains unclear whether short-term spinal cord adaptations are general or task-specific Immediately after task acquisition, neural adaptations were not specific to the trained task (i.e. were general) Twenty-four hours after acquisition, neural adaptations appeared to be task-specific The neural reorganization and generalization of spinal adaptations appears to be time-dependent. ABSTRACT: Spinal cord plasticity is an important contributor of motor learning in humans, although its mechanisms are still poorly documented. In particular, it remains unclear whether short-term spinal adaptations are general or task-specific. As a marker of neural changes that are observable at spinal level, we measured the Hoffmann reflex (H-reflex) amplitude in the soleus muscle of 18 young healthy human adults before, immediately after (acquisition), and 24 h after (retention) the learning of a skilled task (i.e. one-legged stance on a tilt board). H-reflexes were elicited 46 ± 30 ms before touching the tilt board. Additionally, and at the same time points, we measured the H-reflex with the subject sitting at rest and when performing an unskilled and untrained task (i.e. one-legged stance on the floor). After task acquisition, there was a decrease of the H-reflex amplitude measured at rest but not during the skilled or the unskilled task. At retention, there was a decrease of the H-reflex when measured during the skilled task but not during the unskilled task or at rest. Performance increase was not associated with changes in the H-reflex amplitude. After the acquisition of a new skilled task, spinal changes appeared to be general (i.e. observable at rest). However, 24 h after, these changes were task-specific (i.e. observable only during performance of the trained task). These results imply that skill training induces a time-dependent reorganization of the modulation of spinal networks, which possibly reflects a time-dependent optimization of the feedforward motor command.
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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 | 0.000 |
| 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) | 0.003 | 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".