Environmental conditions influence hippocampus‐dependent behaviours and brain levels of amyloid precursor protein in rats
Bibliographic record
Abstract
Sprague-Dawley rats were reared in enriched (EC; group housing, exposure to stimulating objects, frequent handling) or restricted (RC; individual housing, no exposure to stimulating objects, minimal handling) environments starting on day 23 of life. At six months of age, they underwent behavioural tests to assess 'cognitive' and 'stimulus-response' memory, selective attention, and inflammatory pain processing. Alterations in synapses and cell survival may occur as a result of environment differences; therefore we assessed the brain levels of several proteins implicated in neurite outgrowth, synaptogenesis, and cell survival. Brains were dissected and analysed for amyloid precursor protein (APP) and other synaptic and cytoskeletal proteins using Western blotting. The performance of EC animals in a hidden platform water maze task, and in a test of selective attention (both of which are thought to involve the hippocampus) was superior to that of RC animals. In contrast, performance of RC animals on two stimulus-response tasks, the visible platform water maze test and simple visual discrimination (both of which are thought to be hippocampal independent) was indistinguishable from that of EC animals. Male EC rats displayed a different behavioural response to formalin during the inflammatory phase of nociception--the phase affected by hippocampal processing; a similar trend was observed in females. Female but not male RC rats exhibited elevated plasma corticosterone levels; adrenal weights were unaffected by environmental conditions. Region-specific increases in brain levels of APP, neurofilament-70 (NF-70), and platelet-activating factor receptor (PAF-R) were found in EC rats. These data suggest that enriched animals manifest enhanced functioning of certain hippocampus-mediated behaviours when compared with that of their restricted counterparts; and that brain levels of various synaptic and structural proteins involved in neurite outgrowth, cell survival, and synaptogenesis, are affected by environmental factors.
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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 | 0.000 |
| 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".