PM501. Acute Effects of Nicotine and Nabilone on the Mismatch Negativity: A Combined Time-Frequency and Event-Related Potential Study
Bibliographic record
Abstract
Abstract Introduction: While the high prevalence of concomitant cannabis and nicotine use in schizophrenia (SZ) has been viewed as a form of self-medication for cognitive and stress/emotional processing, the interaction of these substances has received limited study in terms of sensory/cognitive processes. The objective of this study was to assess the acute effects of nabilone (synthetic version of THC) and nicotine on the mismatch negativity (MMN) event-related potential, and to evaluate cannabinoid-nicotinic receptor interactions within a pilot study using healthy controls. Methods: 20 male non-smokers and non-cannabis-users were assessed using a 5-stimulus ‘optimal’ multi-feature MMN paradigm within a randomized, double-blind design (placebo; nabilone [0.5 mg]; nicotine [6 mg]; and nicotine + nabilone). The MMN was quantified in the time domain and the time-frequency domain. Results: The separate and combined effects of nicotine and nabilone were region- and deviant-dependent. Temporally, the MMN was impaired by nabilone and nicotine separately, whereas co-administration resulted in no impairment. Frontally, the MMN was enhanced by co-administration of nicotine and nabilone. Nabilone and the combination treatment decreased frontal evoked theta power. Conclusions: It is possible that 1) cannabinoid and nicotinic receptor systems in the frontal and auditory cortex regulating sensory processes are differentially affected, and/or 2) the functional connectivity between the two MMN generators is differentially affected by the two interacting systems. Given the high prevalence rates of tobacco and cannabis use in SZ, understanding the effect of these substances and their interactions on early sensory processes underlying higher-order cognitive processes is of clinical and scientific relevance. Research supported by the Natural Sciences and Engineering Research Council of Canada (Grant #:210572-152799-2001).
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.006 | 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".