Distinct Nicotinic Responses Map onto Electrophysiologically‐ and Morphologically‐Distinct Pyramidal Neurons Within Layer 5 of The Mouse Prefrontal Cortex
Bibliographic record
Abstract
Neurotransmission mediated by acetylcholine at its nicotinic receptors (nAChRs) within the medial prefrontal cortex (mPFC) is critical for higher‐order cognitive tasks. Pyramidal neurons within layer 5 of the mPFC express nAChRs and form the primary signalling outputs from this brain region. These neurons may be categorized as either regular‐firing or initial burst‐firing, based on threshold responses to positive current injection. The objective of this study was to use whole‐cell electrophysiology and biocytin neuron labelling in young postnatal mice (age 15‐20 days) of both sexes to characterize the morphology and nAChR function within each of these neuron categories. When comparing the neuron categories, we first determined that regular‐firing neurons have a greater membrane resistance and spike adaptation ratio, and a lower magnitude post‐firing hyperpolarization. Regular‐firing neurons also exhibited a lower frequency of spontaneous excitatory postsynaptic potentials. Detailed morphological analysis determined that regular‐firing neurons have more apical dendrite matter distal to the soma and more basal dendrite matter proximal to the soma. Pharmacological experiments using receptor‐selective antagonists revealed that nicotinic responses are mediated by distinct nAChR isoforms that are expressed selectively on each of the two pyramidal neuron categories. Specifically, these experiments demonstrate that heteromeric α4β2* nAChRs are present on regular‐firing pyramidal neurons and homomeric α7 nAChRs are present on burst‐firing pyramidal neurons. Ongoing experiments aim to determine the projection targets for each type of pyramidal neuron within each sex. These novel findings suggest a detailed receptor‐based mechanism by which acetylcholine neurotransmission is regulated within output neurons of mPFC layer 5, which may impact the development of cognitive circuits involving this brain region.
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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) | 0.001 | 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".