Differential effects of chronic lithium and valproate on brain activation in healthy volunteers
Bibliographic record
Abstract
RATIONALE: Previous functional imaging studies have shown altered brain activity during cognitive task performance in bipolar patients. However, the fact that these patients are often on medication makes it unclear to what extent these changes reflect treatment effects. OBJECTIVES: This study aims to identify regional brain activity changes occurring following lithium and valproate treatment in healthy volunteers. METHODS: This was a double-blind, placebo-controlled, study in which volunteers received either 1000 mg sodium valproate (n = 12), 900 mg lithium (n = 9), or placebo (n = 12). Functional images were acquired using functional magnetic resonance imaging (fMRI) while subjects performed three cognitive tasks, a word generation paradigm, a spatial attention task and a working memory task. fMRI was carried out both before and after 14 days of treatment with valproate, lithium or placebo. The changes in the magnitude of the blood-oxygen-level-dependent (BOLD) signal after treatment were compared between the groups using a one-way ANOVA for each task followed by a post-hoc multiple comparisons correction. RESULTS: A significant group effect was noted in the change in BOLD signal magnitude from baseline to post-treatment, in all three tasks (working memory p< 0.000; spatial attention task p = 0.003; word generation paradigm p = 0.030). In the working memory task, the lithium group had a significant decrease in BOLD signal change, compared with the control group (p< 0.000). A decrease in BOLD signal change was also noted in the valproate group, in the spatial attention task (p = 0.004). Both lithium and valproate groups had a decreased BOLD signal in the verbal task, following treatment, compared with the placebo group (p = 0.061 (lithium approached significance); p = 0.050 (valproate)). CONCLUSIONS: These findings suggest that lithium and valproate have independent effects on brain activation that vary in a task and region-dependent manner.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| 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 | 0.000 | 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".