engleski

Sagittal strata of the human fetal and neonatal cerebrum

Sagittal strata (SS) appear during early fetal life, form trajectories of projection fibers during midgestation and transform into one of the white matter segments during late fetal period. Aims: to analyze organization of SS on histological sections ; to determine spatial relationship of SS with adjacent cerebral compartments ; to find MRI correlations in vivo and in vitro. Histological sections of postmortem brains, ranging between 8 to 34 postconceptional weeks (PCW), were “stained” for fibrillar and proliferative markers. 20 preterm infants, ranging from 27 to 43 PCW, were MRI examined immediately after preterm birth and at term age. Furthermore, 22 in vitro and 20 cases in utero were also scanned. MRI DTI images were obtained from postmortem brain base Code-No1- HD-4-3368. The results show that early SS appear in the intermediate zone around 10 PCW consisting of thalamic projection and external capsule (EC) basal forebrain fibers. Between 18 to 22 PCW, SS show complex architecture with prominent regional variations and participate in local dispersion of proliferative subventricular zone (SVZ) and migratory waves of cells. External SS is interrupted by radially oriented glial- neuronal migratory stripes and represents important landmark of deep subplate zone during midgestation. In early preterm, basic organization of SS is maintained with increased thickness of external stratum, indicating development of associative fascicles. In vitro and in utero MRI show two bands, medial fibrillar and lateral cellular, which delineate SS. These bands were seen in all preterms with “normal” clinical parameters (SNAPP-II, SNAPP- E-II). At term age, lateral cellular band becomes less visible. In conclusion, projection fibers from basal forebrain and thalamus form SS during early fetal life. Contribution of associative fibers to SS occurs almost two months later. Architecture and developmental changes of SS reflect crucial neurogenetic events and may serve as fine indicator of integrity of the white matter in the human preterm infant.

axonal sagittal strata ; transient cerebral compartments ; development of cerebral connectivity ; white matter integrity

Supp by CSF-IK-09-5417 and CSF-DOK-10-2015.