Characterization of dopaminergic projections from the ventral tegmental area and the dorsal raphe nucleus to the orbital frontal cortex.
Bibliographic record
Abstract
The orbitofrontal cortex (OFC) is a key node in the cortico-limbic-striatal circuitry that influences decision-making guided by the relative value of outcomes. Midbrain dopamine from either the ventral tegmental area (VTA) or the dorsal raphe nucleus (DRN) has the potential to modulate OFC neurons, however it is unknown at what concentrations these terminals release dopamine. Male and female adult DATIRES-CRE-tdTomato mice were injected with AAV2/8-EF1a-DIO-eYFP into either the DRN or VTA or the retrograde label CTB 488 in the medial or lateral OFC. We quantified co-expression of CTB 488 or eYFP with tdTomato fluorescence in VTA or DRN as well as eYFP fiber density in the medial or lateral OFC. Both VTA and DRN dopamine neurons project to either the medial or lateral OFC, with greater expression of fibers in the medial OFC. Using fast-scan cyclic voltammetry, we detected optogenetically evoked dopamine from channelrhodopsin2 (ChR2)-expressing VTA or DRN dopamine terminals in either the medial or lateral OFC. Consistent with increased fiber expression in the medial OFC, dopamine was more reliably detected in this region from optical stimulation of VTA or DRN dopamine terminals. We assessed if optical stimulation of dopamine from the VTA or DRN onto the medial OFC could alter layer V pyramidal neuronal firing; however, we did not observe a change in firing at stimulation parameters which evoked dopamine release from either projection. In summary, dopaminergic neurons from the VTA or DRN project to the OFC and release submicromolar dopamine in the medial and lateral OFC.
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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 | 0.001 | 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) | 0.002 | 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".