Differential Balance of Prefrontal Synaptic Activity in Successful versus Unsuccessful Cognitive Aging
Bibliographic record
Abstract
Normal aging is associated with a variable decline in cognitive functions. Among these, executive function, decision-making, and working memory are primarily associated with the prefrontal cortex. Although a number of studies have examined the structural substrates of cognitive decline associated with aging within this cortical area, their functional correlates remain poorly understood. To fill this gap, we aimed to identify functional synaptic substrates of age-associated frontal-dependent deficits in layer 2/3 pyramidal neurons of medial prefrontal cortex of 3-, 9-, and ≥ 23-month-old Fischer 344 rats. We combined, in the same animals, novelty recognition and exploratory behavioral tasks with assessment of structural and functional aspects of prefrontal synaptic properties. We found that subsets of aged animals displayed stereotyped exploratory behavior or memory deficits. Despite an age-dependent dendritic spine loss, patch-clamp recording of synaptic activity revealed an increase in miniature EPSC frequency restricted to aged animals with preserved exploratory behavior. In contrast, we found a strong positive relationship between miniature IPSC frequency and the occurrence of both stereotyped exploratory behavior and novelty-related memory deficits. The enhanced miniature inhibitory tone was accompanied by a deficit in activity-driven inhibition, also suggesting an impaired dynamic range for modulation of inhibition in the aged, cognitively impaired animals. Together, our data indicate that differential changes in the balance of inhibitory to excitatory synaptic tone may underlie distinct trajectories in the evolution of cognitive performance during aging.
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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".