engleski

Tangential migration in the human telencephalon during second half of gestation

The source of cortical GABA-ergic neurons has unique features in human and non-human primates (Petanjek et. al, Front Neuroanatom 2009 ; 3:26.). In contrast to other mammals, where vast majority if not all are born in ganglionic eminence (GE) and migrate to dorsal telencephalon, in primates about 2/3 of cortical GABA-ergic neurons originate from the local proliferative zones. We have analyzed frontal sectioned slices of the human fetal telencephalon during second half of gestation impregnated by Golgi method. During the period from 22 to 26 postconceptional weeks (pcw) numerous nonradialy oriented migratory like unipolar cells have been observed all around telencephalon, most densely packed in the subventricular and intermediate zones. Also, a large and very densely packed stream of migratory like cells leaving well pronounced GE in direction of dorsal telencephalon was observed at cortico-striatal border. At stage of 32-36 pcw there was still a significant number of nonradially migratory like cells in the dorsal telencephalon, while the GE decreased in size, but was clearly distinguishable. Also, a stream of migratory like cells was extending in ventro-dorsal direction and continuing out of the GE at the position of cortico-striatal border. During whole period many nonradially oriented migratory like cells in dorsal telencephalon, as in the stream leaving GE, were MAP-2 and calretinin positive. These observations suggest that in the human brain significant production of subpopulations of cortical GABA-ergic neurons occurred much beyond proliferative period for principal glutamatergic neurons and extend even to early postnatal period.

interneurons; neurogenesis; tangential migration; ganglionic eminence; outer subventricular zone; MAP-2; calretinin

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