Identifying the Anatomical Layout and Molecular Properties of the GABAA Motivational Switch in the Ventral Tegmental Area
Bibliographic record
Abstract
The motivation to seek natural reinforcers and drugs can transform over time from a form of pleasure-seeking to a form of relief-seeking. This shift from a positive reinforcement-based motivation to a negative reinforcement-based motivation is a hallmark of several substance use and eating disorders. Our group has demonstrated a double dissociation wherein the former motivational state is mediated by the tegmental pedunculopontine nucleus (TPP), while the latter is mediated by mesolimbic dopamine (DA). In this thesis, I demonstrate the functional role that brain-derived neurotrophic factor (BDNF) and connexin-36 (Cx36)-containing gap junctions play in this switching mechanism. Specifically, I show that intra-VTA infusions of BDNF produce a drug-dependent and withdrawn phenotype in otherwise drug-naïve animals and that lentiviral knockdown of the BDNF receptor, TrkB, prevents the manifestation of opiate dependence and withdrawal. I also show that Cx36 is necessary and sufficient for opiate dependence susceptibility, as evidenced by my finding that intra-VTA infusions of the pharmacological blocker, mefloquine, result in a reversion of opiate-dependent and withdrawn (ODW) rats to a drug-naïve state, that conditional knockout mice lacking Cx36 in GAD65+ cells are perpetually drug-naïve, and that viral-mediated rescue of Cx36 in VTA GABA neurons is sufficient to restore susceptibility of those mice to opiate dependence. These studies further characterize the GABAA switch that is causally linked to maladaptive drug-seeking.
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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 | 0.000 |
| 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) | 0.001 | 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".