Multimodal Investigation of Chrna5 Nicotinic Receptors: Cellular and Synaptic Mechanisms of Cholinergic Modulation in the Prefrontal Cortex
Bibliographic record
Abstract
Acetylcholine neurotransmission in the prefrontal cortex is essential for attention and executive function. Its disruption is implicated in multiple neurological disorders with serious cognitive deficits. However, there remain critical knowledge gaps in cellular and synaptic mechanisms of endogenous cholinergic modulation of prefrontal cortex, especially compared to better-characterized sensory cortical regions. In particular, the role of the alpha5 nicotinic receptor subunit encoded by Chrna5, which is expressed in deep-layer neurons in the prefrontal cortex remains unknown. Since Chrna5 is vital for higher-order cognition, it is essential to investigate the synaptic function of alpha5 nicotinic receptors and characterize Chrna5-expressing neurons mediating optimal cholinergic excitation. Here, I examine these questions using a multimodal approach comprising compound transgenics, optogenetics, patch-clamp electrophysiology, two-photon calcium imaging, and transcriptomic analyses in the mouse brain. First, I characterize prefrontal cholinergic signaling in a mouse model with attention deficits caused by genetic ablation of the alpha5 nicotinic subunit. These results identify Chrna5 as necessary for the rapid onset of endogenous cholinergic responses relevant for the fast timescales of attention. Using a nicotinic positive allosteric modulator NS9238, I successfully treat the deficit arising from Chrna5 disruption, restoring rapid onset of cholinergic neurotransmission in alpha5 knockout mice. Next, I probe the identity of Chrna5-expressing (Chrna5+) neurons and molecular determinants of their cholinergic properties. Through multiple approaches in novel Chrna5-Cre transgenic mice, I uncover a distinct population of Chrna5+ neurons with stronger and faster cholinergic responses. With single-cell RNAseq analysis, I identify these cells to be developmentally critical subplate neurons with differential expression of several GPI-anchored Lynx prototoxins. Using optophysiological approaches, I discover complex endogenous modulation of nicotinic receptors by Lynx prototoxins. Overall, this dissertation creates new understanding of prefrontal cholinergic modulation at the synaptic and cellular level. I identify the role of the alpha5 nicotinic subunit in ensuring rapid synaptic cholinergic transmission and preventing desensitization of these nicotinic responses. I discover a specialized subpopulation of Chrna5-expressing neurons with enhanced nicotinic responses that are dynamically regulated by distinct modulatory proteins. Together, my work uncovers molecular and cellular roles of Chrna5 relevant to cognition and identifies novel treatment approaches to restore cholinergic signaling.
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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 | 0.001 |
| 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".