A Conserved Mammalian Hippocampal Navigation Motif Reconfigured for Primate Vision
Bibliographic record
Abstract
Abstract Spatial navigation requires the brain to continuously sample the external world while evaluating internal representations of space. In rodents, this process unfolds through alternating periods of locomotion and pauses. During pauses, hippocampal sharp-wave ripples (SWRs) rates increase, likely reflecting the broadcast of spatial memories that guide navigation. Whether similar dynamics govern navigation in primates remains unknown. Here, we recorded hippocampal activity in freely moving marmosets navigating a 3D maze. Like rodents, marmosets alternated between locomotion and pauses. However, pauses were long and showed an increase in SWR rates relative to locomotion. SWRs were most prominent when animals maintained stable head orientations toward rewarded locations and were reduced during rapid exploratory head movements. SWR rates further increased when spatial memories were used to guide navigation. Our findings reveal a phylogenetically conserved motif linking behavioral states during spatial navigation to hippocampal SWR dynamics across mammals and show how primate visual specializations have adapted this motif to support vision-guided navigation. Significance Statement Our results reveal a phylogenetically conserved hippocampal navigation motif that has persisted despite major evolutionary changes in mammalian sensory ecology. Across species, navigation alternates between external exploration and internal evaluation, with SWRs marking periods of memory-guided computation. However, primate evolution reshaped the behavioral expression of this motif by coupling it to active visual sampling, gaze control, and foveal inspection of landmarks. Thus, evolution appears to have preserved a core hippocampal algorithm for navigation while adapting its sensory inputs and behavioral context to the demands of diurnal, vision-guided life.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 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 | 0.001 | 0.001 |
| 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".