Impaired presynaptic inhibition in the motor cortex in Parkinson disease
Bibliographic record
Abstract
OBJECTIVE: Intracortical inhibition in the motor cortex may be measured with short interval intracortical inhibition (SICI), likely mediated by GABA(A) receptors, and long interval intracortical inhibition (LICI), likely mediated by GABA(B) receptors. Separate neuronal populations mediate SICI and LICI, and LICI inhibits SICI, likely through GABA(B) mediated presynaptic inhibition. The purpose of this study was to test the hypothesis that cortical presynaptic inhibition in Parkinson disease (PD) is impaired. METHODS: Eleven patients with PD were studied at rest both OFF and ON dopaminergic medications and the results were compared to nine healthy, age-matched controls. Motor evoked potentials were recorded from the first dorsal interosseous muscle and a triple-stimulus transcranial magnetic stimulation paradigm was used to evaluate SICI in the presence of LICI. The interstimulus interval (ISI) for SICI was 2 msec and LICI was studied at 100 (LICI(100)) and 150 msec (LICI(150)) ISIs. RESULTS: There was no difference in SICI between the controls and PD ON and PD OFF groups. LICI(100) was stronger than LICI(150) and both were reduced in the PD ON and OFF groups. LICI(100) led to a much greater reduction in SICI in the control group compared to both the PD OFF and ON groups. LICI(150) caused no significant change in SICI with no significant difference between the controls and PD OFF and PD ON groups. CONCLUSIONS: The inhibitory effect of long interval intracortical inhibition on short interval intracortical inhibition, likely representing presynpatic inhibition in the motor cortex, is decreased in Parkinson disease and may be a nondopaminergic feature of the disease.
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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 | 0.000 |
| 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) | 0.000 | 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".