The unilateral 6‐OHDA rat model of Parkinson's disease revisited: an electromyographic and behavioural analysis
Bibliographic record
Abstract
The characteristic locomotor disturbances of Parkinson's disease (PD) include shuffling gait, short steps and low walking velocity. In this study we investigated features of walking and turning in a rat model of PD caused by unilateral infusion of the neurotoxin 6-hydroxydopamine (6-OHDA). We assessed gait and electromyographic (EMG) patterns of the ankle flexor tibialis anterior and the knee extensor vastus lateralis of the hindlimb, and triceps brachii of the forelimb, during overground locomotion, spontaneous rotation (turning) and apomorphine-induced rotation. When compared with control rats, rats with unilateral dopamine depletion displayed a shuffling gait and short stride lengths. This locomotor pattern was accompanied by prolonged ankle flexor activity on the ipsilateral side, and prolonged activity of knee extensors on the contralateral side. The dopamine depletion also led to enhanced contraversive rotations after an apomorphine challenge. The EMG recordings during drug-induced rotation suggested that hindlimb stepping was a reflective response to an active drive produced by forelimbs. The EMG recordings of the contralateral side during rotation were marked by reduced ankle flexor activity and increased knee extensor activity. Furthermore, EMG recordings indicated that dopamine-agonists induce rotational bias by altering the coupling between ipsi- and contralateral hindlimbs, and between forelimbs. In straight walking, however, the gait of 6-OHDA lesion animals reflected normal, coupled hindlimb stepping as controlled by spinal pattern generators. The data suggest that the unilateral rat model of PD resembles key features of human parkinsonian gait, and that asymmetric descending input may underlie the observed changes in gait patterns.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
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".