P4‐101: Functional neural mechanisms underlying executive functioning in mild cognitive impairment and Alzheimer's disease: An EEG coherence study
Bibliographic record
Abstract
Executive dysfunction is present in mild cognitive impairment (MCI) and early Alzheimer's disease (AD); however, its neural substrates remain unclear. AD may involve disconnection between brain areas, thus, we measured functional connection between brain areas using EEG coherence in normal elderly controls (NECs), MCI, and AD during executive task performance to determine the relationship between executive functioning (EF) and functional connections in these groups. 30 NECs, 15 MCI, and 10 early AD patients completed neuropsychological and EEG testing. EEG was recorded while performing two EF tasks: go/no-go (inhibitory control) and n-back (working memory). EEG coherence was calculated for frontal (F3-F4) and parietal (P3-P4) interhemispheric electrode pairs as well as fronto-parietal interhemispheric (F3-P4, F4-P3) and intrahemispheric (F3-P3, F4-P4) electrode pairs in the theta and gamma frequency bands. Preliminary analyses revealed that AD patients performed worse than NECs on all EF measures and MCI patients exhibited a deficit on inhibition measures, but not other EF tasks. There were no group differences for the go/no-go task. For n-back, AD patients had slower reaction times, and AD and MCI patients had lower accuracy. EEG coherence in conditions requiring EF was higher than in control conditions for all groups and all electrode pairs in the theta and gamma bands. Coherence in the theta band during go/no-go was lower for AD versus NECs for F3-F4, P3-P4, and F3-P4 electrode pairs. Correlations for coherence variables that showed group differences in AD patients revealed a that higher coherence was related to better performance on select neuropsychological tests for F3-F4, F3-P3, F3-P4, and F4-P3 electrode pairs. This study demonstrated that EEG coherence in gamma and theta bands changes parametrically with the manipulation of executive demands in NECs, MCI, and AD. Decreased coherence was observed in AD for certain electrode pairs in the theta band, and coherence for those pairs correlated with performance on selected neuropsychological measures. Thus, decreased interhemispheric coherence in frontal and fronto-parietal regions may be an underlying neural mechanism for executive dysfunction in early AD. The current findings may provide a useful, inexpensive method of demonstrating functional disconnections between brain areas due to the neuropathology of AD.
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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) | 0.000 | 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) | 0.002 | 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".