µ-Opioid Receptor Control of Glutamate/GABA Coreleasing SUM and VTA Projections to the Dentate Gyrus
Bibliographic record
Abstract
The dentate gyrus (DG) is a hippocampal structure responsible for filtering cortical input and conveying it to CA3, where it forms associative memories. Granule cells, the principal excitatory neurons of the DG, have extensive dendritic arbors that occupy the molecular layer of the DG. The excitability of these neurons is tightly controlled by GABAergic basket cells, which synapse onto the proximal dendrites and soma of granule cells (Amaral et al., 2007). While granule cells receive the majority of their inputs from the entorhinal cortex, other cortical and subcortical structures provide input that modulates granule cell activity. For example, DG receives input from the ventral tegmental area (VTA) and the supramammillary nucleus (SUM), midbrain structures involved in control of motivation and learning (Ntamati and Lüscher, 2016; Hashimotodani et al., 2018). The VTA is best known for regulating reward and aversion behaviors through dopamine release, but its dopaminergic projections to the hippocampus are quite sparse (Han et al., 2020). Instead, most VTA–DG projections corelease glutamate and GABA. Activation of these projections reduces granule cell firing in anesthetized animals (Ntamati and Lüscher, 2016). Chemogenetic inactivation of these projections impairs acquisition and reinstatement of fear conditioning in mice, suggesting they aid the formation and retrieval of emotionally valent memories (Han et al., 2020). SUM–hippocampus projections also corelease glutamate and GABA, and they synapse onto both granule cells and surrounding interneurons. Recent studies show that stimulation of SUM fibers causes an overall increase in granule cell activity (Hashimotodani et al., 2018) and inactivation of these projections in vivo impairs retrieval of spatial memories (Li et al., 2020). They have also been linked to emotional memory processing. Granule cell activity is also regulated by activation of µ-opioid receptors (MOR), which are abundantly expressed in the DG, rendering it susceptible to the effects of MOR … Correspondence should be addressed to Daria Oleinichenko at daria.oleinichenko{at}ubc.ca.
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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 | 0.001 |
| 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".