Effects of subthalamic nucleus stimulation on motor cortex excitability in Parkinson’s disease
Bibliographic record
Abstract
BACKGROUND: Transcranial magnetic stimulation (TMS) studies have found abnormalities in several excitatory and inhibitory circuits in the motor cortex in PD. These include motor evoked potential (MEP) recruitment curve, silent period duration (SP), short-interval intracortical inhibition (SICI), intracortical facilitation (ICF), and long-interval intracortical inhibition (LICI). METHODS: The authors studied the effects of subthalamic nucleus (STN) deep brain stimulation (DBS) on these circuits in 12 patients with PD treated with STN DBS. Data from nine patients who completed the study were analyzed. Patients remained on their usual medications. The stimulators were set at the optimal parameters (ON), half the optimal amplitude (HALF), and switched off (OFF) in random order. RESULTS: The Unified PD Rating Scale motor scores were significantly lower in the ON compared to the HALF and OFF conditions. Resting SICI, studied with paired-pulse TMS at interstimulus interval of 2 ms, was reduced in the OFF and HALF conditions compared to normal subjects. STN stimulation restored SICI to normal levels. STN stimulation had no effect on motor threshold, MEP recruitment curve, SP, active SICI, ICF, and LICI. CONCLUSIONS: Although restoration of short-interval intracortical inhibition by STN stimulation is similar to the effects of dopaminergic drugs, it has no effect on silent period duration and long-interval intracortical inhibition, which are also influenced by dopaminergic drugs. A previous study found that internal globus pallidus (GPi) stimulation reduced SP but did not change SICI. Thus, GPi and STN stimulation may affect different circuits in the motor cortex.
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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".