IC‐P‐159: FRONTAL LOBE HYPERACTIVATION DURING WORKING MEMORY IN PERSONS WITH MCI
Bibliographic record
Abstract
Recent studies have shown greater task-related activation in individuals with mild cognitive impairment (MCI) compared to healthy older adults. It has been suggested that these hyperactivations reflect compensatory processes of brain plasticity in the early phase of AD. When there is loss of structural integrity of a brain region that is typically required for a specific task, functional compensation processes may emerge through increased activation of specialized, adjacent or controlateral regions. This hypothesis was examined in MCI using a working memory task that incorporated a parametrical variation of difficulty level as well as functional and structural magnetic resonance imaging (MRI). Twenty-one older adults participated in this study; eleven with MCI and ten with no cognitive impairment. Participants completed an N-back working memory task with two levels of difficulty (1 and 2-back) presented in a block design. Structural and functional images were aquired using 3T SIEMENS Magnetom TIM TRIO. No group differences in accuracy were found, however, there were marked group differences in terms of brain activation. As expected, frontal lobe activation increased as a function of task difficulty in healthy older adults. Furthermore,significantly greater BOLD signals were observed in MCI than healthy controls. Hyperactivation was found bilaterally in the anterior cingulate and medial frontal cortex for the 1-back condition, and in the left hemisphere for the 2-back condition. Extracted β values from the right hemisphere activation cluster in the MCI group were found to negatively correlate with the volume of the right rostral middle frontal area in the 1-back condition. Regions within the frontal lobe are progressively more recruited as the task increases in difficulty. Similarly, individuals with MCI appear to have greater activation than controls in the brain regions typically involved in working memory. Interestingly, the group difference in activation diminished in the 2-back condition as the control participants increasingly recruited regions that had been solicited by the MCI group during the 1-back condition. The negative correlation found between activation and brain volume in the frontal cortex in MCI participants suggests that these hyperactivations reflect compensatory processes as brain regions become structurally impaired.
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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 | 0.001 | 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".