P3‐240: Blink‐Related Oscillations as Potential Measure of Default Mode Network (DMN) Activity in Alzheimer’S Disease
Bibliographic record
Abstract
The default mode network (DMN) is a set of brain regions with increased activity at rest, which is disrupted in AD. Though it is a promising clinical marker of AD, the use of large-scale equipment like functional magnetic resonance imaging (fMRI) to study the DMN is not ideal for clinical utility. New evidence from electroencephalography (EEG) suggests that there may be a cognitive component associated with spontaneous blinks at rest that also originates from the DMN. These blink-related oscillations (BROs) offer a potential new avenue to access the DMN using EEG. However, a better understanding is needed regarding the neurocognitive mechanism of BROs. Since magnetoencephalography (MEG) has superior spatial resolution compared to EEG, the current study aims to characterize the neurological mechanisms of BROs using MEG. Ten-minute resting state data were collected on 40 healthy control participants (age 18-40) using 151-channel MEG with simultaneous electrooculogram (EOG) recording. Preprocessing was performed as previously described. Briefly, blink instances were identified through convolution of vertical EOG plus amplitude and temporal thresholding. Ocular artifact was rejected through independent component analysis (ICA) of MEG channels. Sensor level analysis was performed by filtering (0.3-3Hz) and averaging across trials. Source localization was performed using the Minimum Norm technique in Statistical Parametric Mapping (SPM8). Preliminary results at the sensor level show that there is increased magnetic field activity in the delta frequency range (0.5-3Hz) occurring 300-400ms post-blink, consistent with prior studies using EEG. Source location identified increased activity in areas of the parietal, temporal, and frontal lobes consistent with the DMN, occurring in the 500ms post-blink interval relative to pre-blink (FWE p<0.001). To our knowledge, this is the first study of BRO activity using MEG. Our preliminary results suggest BROs originate from regions within the DMN. Continuing work examines activity in other frequency bands, and involves time-frequency, region-of-interest, as well as functional connectivity analyses. BROs may provide an exciting new avenue for accessing the DMN as a clinical marker for 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) | 0.003 | 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".