Voltage imaging reveals hippocampal inhibitory dynamics shaping pyramidal memory-encoding sequences
Bibliographic record
Abstract
Hippocampal spiking sequences encode and link behaviorally relevant information across time. How inhibition sculpts these sequences remains unclear. We performed longitudinal voltage imaging of CA1 parvalbumin- and somatostatin-expressing interneurons in mice performing an odor-cued working memory task. Unlike pyramidal odor-specific sequences that encode odor and time throughout a delay period, interneurons encoded odor delivery, but not odor identity or delay time. Odor-triggered inhibition was exerted by stable numbers of interneurons across days, with constant cell turnover, independent of task training. At odor onset, brief spiking of parvalbumin interneurons was followed by widespread hyperpolarization and synchronized theta-paced rebound spiking across interneurons. Electrophysiology, optogenetics and calcium imaging corroborated that parvalbumin interneurons silenced most pyramidal cells during odor delivery, whereas somatostatin interneurons suppressed other interneurons. The few odor-selective pyramidal cells spiked together with interneuronal post-hyperpolarization rebound. Collectively, inhibition increases the signal-to-noise ratio of pyramidal cue representations, enabling efficient encoding of memory-relevant information.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.006 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.004 |
| Science and technology studies | 0.002 | 0.002 |
| Scholarly communication | 0.001 | 0.002 |
| Open science | 0.003 | 0.001 |
| Research integrity | 0.000 | 0.003 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".