IC‐P1‐059: Activation of dorsolateral prefrontal cortex during rest in early Alzheimer's disease: A preliminary study using 4 Tesla fMRI
Notice bibliographique
Résumé
Functional MRI studies on Alzheimer's disease (AD) often examine task-related activation, for which images taken during one cognitive state are compared with those during a reference state. When the resting state serves as this reference, inter-group differences in fMRI activation patterns thus may result from differences between the groups in baseline neural activity. We examined fluctuations of fMRI activation at rest in mild AD patients and in cognitively intact older adults. We began with a focus on the dorsolateral prefrontal cortex (DLPFC) as a region of interest because of its role in executive functions and working memory, and because of its frequent involvement in fMRI studies of cognitive tasks. Four patients with mild AD and eight healthy older adults were scanned on a 4-Tesla Varian-Oxford human imaging system. The subjects were instructed to remain relaxed while focusing their eyes on a central fixation for over 60 seconds. Functional images were acquired using two-shot spiral readout; 22 axial slices of 5.5+0.5mm. Data were processed using independent component analysis and artifacts attributed to physical and physiological sources were filtered. The time course of the representative resting state components (ICs) that were common across AD and healthy subjects were identified and analyzed applying GLM (p=0.001, uncorrected, extent=6). Signal changes, measured as the percentage difference between the highest and lowest of three consecutive fMRI data points during a scan were calculated. The fMRI signals filtered for known imaging signal to noise ratio and physiological variations fluctuated during the resting phase. Three ICs were identified across subjects with each being characterized as a low frequency response (<0.08Hz). Within the DFPLC, both the mean percentage change of the signal and the statistics in the contrast maps (i.e., for an IC) were greater in AD patients than in cognitively healthy older subjects. Regular patterns of fluctuations in fMRI indices of neural activity exist during rest and patients with mild AD demonstrated increased resting-state DLPFC activity. These resting state differences may reflect an early neurocompensatory response to AD.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».