Analiza kvantitativnih i kvalitativnih promjena fetalnih zona, prikazanih magnetskom rezonancijom, kao pokazatelja glavnih histogenetskih događaja u normalnom razvoju ljudskog mozga
Notice bibliographique
Résumé
Before the birth the human telencephalon undergoes dynamic changes. The fetal telencephalic wall is built of transient fetal zones. These transient fetal zones are sites of occurence of the most important neurogenetic and histogenetic processes. As a result of intertwined complex neurogenetic events, morphological characteristics of the fetal telencephalon change depending on the age and the stage of development. Imaging of fetal telencephalon using magnetic resonance imaging thus allows quantitative measurements of transient fetal zones of the developing brain. Moreover, as qualitative MRI reflects the microstructural content (cell volume, the amount of fibres and extracellular space), the qualitative MRI information can be used as a basis for quantitative analysis. To determine the most important quantitative indicators, depending on the stage of development, the dominant neurogenetic events are analyzed and reconstructed within the framework of dynamical change in volume of transient fetal zones and their regional three-dimensional changes in thickness. \nNineteen post-mortem fetal brains, aged 11 to 40 post-conceptional weeks (PCW), were obtained and scanned using the 3T Siemens MRI device. The MRI images were analyzed using programs developed at McGill University specifically designed for the analysis of postmortem fetal brains. \nThe results obtained by calculating the volume of transient fetal zones suggest that the subplate zone represents the most important zone during the development of human telencephalon. Up to 30 PCW, it occupies about 40% of the total volume of telencephalon. The volume of proliferative zones, during the fetal stage of development (13 - 23 PCW), increases and reaches its peak value at 23 PCW. The increase in the volume of proliferative zones coincides with the dynamics and the peak wave of migration and proliferation of neuronal precursors described in literature. Thus, it can be used as one of biomarkers for the fetal stage of development. Furthermore, correlation matrices derived from regional analysis of subplate zone volumes (reaching the total volume peak at 30 PCW), regional cortical plate volumes (the total volume accelerates and exponentially increases after the 30 PCW) and between them suggest that the interaction of histogenetic changes (indirectly seen as postive and negative correlation between regional volumes), such as the ingrowth of axons in the subplate zone and the ingrowth of axons into the cortical plate, are important for the maturation of the cortex during the fetal stage of prenatal development. In addition, regional differences in the thickness and volume of the subplate zone and their correlation with the regional growth of the cortical plate from 24 PCW, indicate that the subplate zone, the site of the main neurogenetic events crucial for normal growth of axonal pathways, is important for normal growth and maturation of the cerebral cortex. \nIn conclusion, the results of this study confirm the hypothesis that quantitative indicators estimated from MR images of the human postmortem fetal brains may serve as indicators for the main neurogenetic events that occur in transient fetal zones and thus have a clear potential as biomarkers of normal and abnormal human brain development.
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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 | 0,001 | 0,002 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,004 | 0,002 |
| Études des sciences et des technologies | 0,000 | 0,001 |
| Communication savante | 0,001 | 0,001 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,004 | 0,001 |
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 ».