Homeostatic regulation of presynaptic NMDA receptor subunit composition modulates action potential driven Ca <sup>2+</sup> influx into boutons setting the bandwidth for information transfer
Bibliographic record
Abstract
Summary N-Methyl-D-aspartate receptors (NMDARs) play a pivotal role in both short and long-term plasticity. While the functional role of postsynaptic NMDARs is well established, a framework of presynaptic NMDAR (preNMDAR) function is missing. Differences in subunit composition of preNMDARs are documented at central synapses, raising the possibility that subtype composition plays a role in transmission performance. Here, we use electrophysiological recordings at Schaffer collateral - CA1 synapses and Ca 2+ imaging coupled to focal glutamate uncaging at boutons of CA3 pyramidal neurones to reveal two populations of presynaptic NMDARs that contain either the GluN2A or GluN2B subunit. Activation of the GluN2B population decreases action potential (AP)-evoked Ca 2+ influx via modulation of small conductance Ca 2+ -activated K + channels (SK-channels) while activation of the GluN2A containing population does the opposite. Moreover, the level of functional expression of each receptor population can be homeostatically modified, bidirectionally affecting short-term facilitation during burst firing, thus providing a capacity for a fine adjustment of the presynaptic integration time window and therefore the bandwidth of information transfer.
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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 | 0.000 |
| 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".