engleski

Tbr1 as a key indicator for cortical plate cells spread down during the primate characteristic subplate expansion period in the human fetal cortex

Transient fetal zones are a characteristic feature of the developing human cerebral cortex. Neurons are born in the proliferative zones: ventricular (VZ) and subventricular zone (SVZ). Afterward, newly born neurons migrate through the intermediate zone (IZ) and subplate (SP) to reach their final destination, the cortical plate (CP). Development of the cortical anlage begins with the formation of preplate – PP (mantle by His), which is split by the cohort of CP cells in that way the specific marginal zone (MZ) containing Cajal- Retzius neurons (CRN) and presubplate (P- SP) are formed. During the early fetal period, P- SP is already present below the cortical plate, while the expanded SP is formed between 13 PCW and 15 PCW (SP formation period) as a key event in the corticogenesis of humans and other primates. Cells of the deep CP are secondarily dispersed downwards (second cortical plate), forming the future expanded SP. Tbr1 is a transcription factor highly expressed in the preplate and CP, and later in the SP and deep CP, suggesting its major role in cortical development. Reelin is a glycoprotein secreted by CRN in the MZ, playing a major role in neuronal radial migration. Our study aimed to show the expression dynamics of Tbr1, marker of future SP neurons, and Reelin, during the early and midfetal period with the special emphasis on the SP formation period. We showed that Tbr1 is a reliable marker of CP cells` „displacement“ and final laminar destination during human specific key event of corticogenesis – SP formation period.

human brain development ; cerebral cortex ; subplate ; Tbr1

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