Effects of Apomorphine on Subthalamic Nucleus and Globus Pallidus Internus Neurons in Patients With Parkinson's Disease
Bibliographic record
Abstract
This study examines the effect of apomorphine (APO), a nonselective D(1)- and D(2)-dopamine receptor agonist, on the firing activity of neurons in the subthalamic nucleus (STN) and internal segment of the globus pallidus (GPi) in patients with Parkinson's disease (PD). Single-unit microelectrode recordings were conducted in 13 patients undergoing implantation of deep brain stimulation electrodes in STN and 6 patients undergoing a pallidotomy. Doses of APO (2.5-8 mg) were sufficient to produce an ON state, but not intended to induce dyskinetic movements. Following baseline recordings from a single neuron, APO was administered and the activity of the neuron followed for an average of 15 min. The spontaneous discharge of neurons encountered before (n = 309), during (n = 146, 10-60 min), and after the effect of APO had waned (n = 127, >60 min) was also sampled, and the response to passive joint movements was noted. In both nuclei, APO increased the overall proportion of spikes in burst discharges (as detected with Poisson "surprise" analysis), and a greater proportion of cells with an irregular discharge pattern was observed. APO significantly decreased the overall firing rates of GPi neurons (P < 0.01), but there was no change in the overall firing rate of neurons in the STN (P = 0.68). However, the mean firing rates of STN neurons during APO-induced movements (choreic or dystonic dyskinesias) that occurred in four patients were significantly lower than OFF-period baseline values (P < 0.05). Concurrent with a reduction in limb tremor, the percentage of cells with tremor-related activity (TCs) was found to be significantly reduced from 19 to 6% in the STN and 14 to 0% in the GPi following APO administration. APO also decreased the firing rate of STN TCs (P < 0.05). During the OFF state, more than 15% of neurons tested (STN = 93, GPi = 63) responded to passive movement of two or more joints. After APO, this proportion decreased significantly to 7% of STN cells and 4% of GPi cells (STN = 28, GPi = 26). These findings suggest that the APO-induced amelioration of parkinsonian symptoms is not solely due to a decrease in overall activity in the GPi or STN as predicted by the current model of basal ganglia function in PD.
Stored with the screening record, where it is evidence for the labels above.
How this classification was reachedexpand
The three-model screen
all 5,600 screened works →All three models called this out of scope.
Neurophysiology of apomorphine effects on basal ganglia neurons in Parkinson's disease.
This is a clinical neuroscience study of apomorphine effects in Parkinson's disease.
Clinical neurophysiology study of apomorphine effects on basal ganglia neurons.
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) | 0.000 | 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 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".