NR2B-subunit dependent facilitation of long-term potentiation in primary visual cortex following visual discrimination training of adult rats
Bibliographic record
Abstract
Long-term potentiation (LTP) is an important mechanism thought to mediate changes in synaptic connectivity following various types of experience. We examined the effects of visual discrimination training on LTP in the mature, rodent thalamocortical visual system. Adult rats underwent visual discrimination training in a modified Morris Water Maze containing a Y-maze insert, requiring rats to associate visual cues with the location of a hidden escape platform placed in one of the two goal arms of the Y-maze insert. On the day following successful task acquisition (average of nine training days), rats were anesthetized (urethane), and LTP in the thalamocortical system was characterized. In task-naïve rats, theta-burst stimulation of the lateral geniculate nucleus resulted in modest (∼40%) potentiation of field postsynaptic potentials recorded in the primary visual cortex (V1). Rats trained on the visual discrimination task showed significantly greater levels of LTP (∼60%), an effect that was not seen in rats trained to swim in the maze without a predictive association between visual cues and platform location. An antagonist of the N-methyl-d-aspartate (NMDA) receptor NR2B subunit ([R-(R *,S *)]-α-(4-hydroxyphenyl)-β-methyl-4-(phenylmethyl)-1-piperidinepropanol hydrochloride (Ro 25-6981); 2 mm, applied locally at the recording site in V1) reversed the training-induced LTP enhancement without affecting LTP in task-naïve rats. An antagonist of metabotropic glutamate receptors [(2S)-2-amino-2-[(1S,2S)-2-carboxycycloprop-1-yl]-3-(xanth-9-yl) propanoic acid (LY 341495); 2 mm] was ineffective in reversing the training-induced LTP facilitation. These data suggest that behavioral (visual) training can result in changes in plasticity exhibited by the mature, thalamocortical visual system that require activation of NMDA receptors containing the NR2B subunit.
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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".