Differential effects of propofol on gamma-band activity across cortical and thalamic sites in the rat, «in vivo»
Bibliographic record
Abstract
Objective. Gamma (γ) oscillations (30-200 Hz) are intrinsic brain rhythms that are important for arousal and conscious processes. Although general anesthetics (GAs) cause concentration-dependent reductions of γ activity evoked by stimulation, their effect on spontaneously occurring γ oscillations remain largely unclear. The author investigated the concentration-dependent effects of propofol on behavior and spontaneous γ-oscillations. Methods. Adult male Long-Evans rats (n=9) were chronically implanted with electrodes in the barrel cortex and ventroposteromedial thalamus. Spontaneous γ-power was assessed over different propofol plasma-concentrations (0, 3,6,9,12 μg/ml, and recovery) and frequency ranges (30-50, 51-75, 76-125, 126-500 Hz). Behavior was scored based on rearing, ambulation and jumping (n=6).Anesthesia was defined as loss of righting reflex. Results. Anesthesia occurred at the 9μg/ml concentration. Three patterns of γ-power change were identified. The first one was an inverted-U shaped pattern found within cortical (30-75 Hz) and thalamic (30-50 Hz) recordings. The second was a plateau-drop pattern, representing no change across sub-anesthetic concentration, followed by a drop with onset of anesthesia. This occurred in the cortex (76-200 Hz) and thalamus (51-75 Hz). Finally a concentration-dependent linear decline pattern was observed in the thalamus across the 76-125 Hz and 126-200 Hz range. Increased ambulation and jumping was observed at sub-anesthetic concentrations coinciding with the inverted-U shape pattern. Conclusions. These results demonstrate that the effects of GAs effect on spontaneous γ oscillations depend on drug concentration, recording site and frequency range investigated.
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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".