Probing peripheral and central cholinergic system responses.
Bibliographic record
Abstract
OBJECTIVE: The pharmacological response to drugs that act on the cholinergic system of the iris has been used to predict deficits in central cholinergic functioning due to diseases such as Alzheimer's disease, yet correlations between central and peripheral responses have not been properly studied. This study assessed the effect of normal aging on (1) the tropicamide-induced increase in pupil diameter, and (2) the reversal of this effect with pilocarpine. Scopolamine was used as a positive control to detect age-dependent changes in central cholinergic functioning in the elderly. DESIGN: Randomized double-blind controlled trial. PARTICIPANTS: Ten healthy elderly (mean age 70) and 9 young (mean age 33) volunteers. INTERVENTIONS: Pupil diameter was monitored using a computerized infrared pupillometer over 4 hours. The study involved 4 sessions. In 1 session, tropicamide (20 microL, 0.01%) was administered to one eye and placebo to the other. In another session, tropicamide (20 microL, 0.01%) was administered to both eyes, followed 23 minutes later by the application of pilocarpine (20 microL, 0.1%) to one eye and placebo to the other. All eye drops were given in a randomized order. In 2 separate sessions, a single dose of scopolamine (0.5 mg, intravenously) or placebo was administered, and the effects on word recall were measured using the Buschke Selective Reminding Test over 2 hours. OUTCOME MEASURES: Pupil size at time points after administration of tropicamide and pilocarpine; scopolamine-induced impairment in word recall. RESULTS: There was no significant difference between elderly and young volunteers in pupillary response to tropicamide at any time point (p > 0.05). The elderly group had a significantly greater pilocarpine-induced net decrease in pupil size 85, 125, 165 and 215 minutes after administration, compared with the young group (p < 0.05). Compared with the young group, the elderly group had greater scopolamine-induced impairment in word recall 60, 90 and 120 minutes after administration (p < 0.05). CONCLUSION: There is an age-related pupillary response to pilocarpine that is not found with tropicamide. Thus, pilocarpine may be useful to assess variations in central cholinergic function in elderly patients.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 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) | 0.004 | 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".