Responses of Cerebellar Interpositus Neurons to Predictable Perturbations Applied to an Object Held in a Precision Grip
Bibliographic record
Abstract
Two monkeys were trained to lift and hold an instrumented object at a fixed height for 2.5 s using a precision grip. The device was equipped with load cells to measure both the grip and lifting or load forces. On selected blocks of 20-30 trials, a downward force-pulse perturbation was applied to the object after 1.5 s of stationary holding. The animals were required to resist the perturbation to obtain a fruit juice reward. The perturbations invariably elicited a reflex-like, time-locked increase in grip force at latencies between 50 and 100 ms. In this study, we searched for single cells in the interpositus and dentate nuclei with activity related to grasping and lifting, and we tested 127/150 task-related cells for their responses to the perturbation. Of the 127 cells, reflex-like increases or decreases in discharge frequency occurred in 75 cells (59%) at a mean latency of 36 ms. Preparatory increases in grip force preceding the perturbation appeared gradually and increased in strength with repetition in 39/127 (31%) cells. These preparatory increases did not immediately disappear when the perturbations were withdrawn but decreased progressively over repeated trials. Although a few cells showed anticipatory activity without a reflex-like response (15/127 or 12%), the majority of these cells (24/39) displayed both anticipatory and reflex-like responses. From an examination of the histological sections, cells with both anticipatory and reflex-like responses appeared to be confined to the dorsal anterior interpositus, adjacent to, but not within, the dentate nucleus. These results confirm and extend the suggestion by Dugas and Smith that the cerebellum plays a major role in organizing anticipatory responses to predictable perturbations in a manner that medial and lateral premotor areas of the cerebral cortex do not.
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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 | 0.000 | 0.001 |
| 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) | 0.000 | 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".