Selective Modification of Short-Term Hippocampal Synaptic Plasticity and Impaired Memory Extinction in Mice with a Congenitally Reduced Hippocampal Commissure
Bibliographic record
Abstract
The hippocampus is critical for forming new long-term memories, but the contributions of the hippocampal commissure (HC) to memory function and hippocampal synaptic plasticity are unclear. To shed light on this issue, we characterized behavioral memory and hippocampal synaptic plasticity in two inbred mouse strains. BALB/cWah1 mice display a range of corpus callosal defects and an intact HC, whereas 9XCA/Wah mice exhibit a complete absence of corpus callosum and a greatly reduced HC. No differences between strains were found in long-term potentiation (LTP) within two synaptic pathways in hippocampal slices. However, paired-pulse facilitation was deficient in area CA1 of slices from 9XCA/Wah, and it was rescued by decreasing extracellular [Ca2+], suggesting that presynaptic calcium dynamics may be altered in this strain. In addition, contextual fear extinction was impaired in 9XCA/Wah mice, but performance on cued fear extinction and on 24 hr memory tests for cued and contextual fear conditioning were not significantly different between strains. Thus, an intact HC is critical for normal extinction of contextual fear. Intact interhemispheric connectivity is not required for acquisition or expression of cued and contextual fear conditioning. LTP was normal in slices from mice that lacked an intact HC, and this was correlated with normal performance on fear conditioning tests. In contrast, impaired short-term synaptic plasticity was correlated with defective contextual memory extinction in mice lacking an intact HC. Thus, the HC in mice is vital for particular aspects of memory function and for short-term synaptic modification in specific hippocampal circuits.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.002 |
| 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".