Analiza kvantitativnih i kvalitativnih promjena fetalnih zona, prikazanih magnetskom rezonancijom, kao pokazatelja glavnih histogenetskih događaja u normalnom razvoju ljudskog mozga
Bibliographic record
Abstract
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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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 | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.004 | 0.002 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.004 | 0.001 |
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".