Reduced Dendritic Spine Density on Hippocampal Granule Cells is Associated with High Anxiety in Rats: Implications for PTSD
Bibliographic record
Abstract
Noor Shakfeh (1), Natalie Meylan (2), Robert Adamec (3), Ronald F. Mervis (2, 4) (1) The Honors College, USF, Tampa, FL; (2) Neurostructural Research Labs, Tampa, FL.; (3) Dept of Psychology, Memorial University, St. John’s, Newfoundland, Canada, (4) Center of Excellence for Aging and Brain Repair, Dept of Neurosurgery and Brain Repair, USF College of Medicine, Tampa, FL. Post-Traumatic Stress Disorder (PTSD) is an anxiety response to severe stress. There are individual differences in vulnerability. Not all individuals exposed to the same stressor show PTSD. The purpose of this study was to ascertain the relationship between anxiety levels and hippocampal brain circuitry: spine density on granule cells of the dentate gyrus. Predator stress (exposure to a cat) is an intense stressor. The response to the predator stress is also contingent upon whether the subject’s innate level of anxiety is low (e.g, well adapted) or high (e.g., mal-adapted). In a rat, this anxiety can be determined by an elevated plus maze. There were 4 groups of adult rats. Rats categorized as “less anxious” were either non-stressed (controls) or predator stressed; and, “high anxious” rats were also either non-stressed or predator stressed. Fixed brains were Golgi stained and from coded slides dendritic spine density was assessed. Spine density in high anxiety rats had significantly lower spine densities. Regardless of whether the rats were stressed or non-stressed, high anxiety rats had 10-13% fewer dendritic spines on their granule cells compared to the low anxiety rats. Thus hippocampal circuitry in the high anxiety rats is significantly altered from the low anxiety group.
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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".