Intracortical multidirectional migration of cortical interneurons

摘要

It is well documented that most cortical interneurons originate from the basal forebrain and migrate tangentially to the cortex. However, relatively little is known about their migration after their arrival at the cortex. To elucidate the route and mode of intracortical migration of the interneurons, we performed real-time analysis by utilizing glutamate decarboxylase (GAD) 67/green fluorescence protein (GFP) knock-in mice and an electroporation-based gene transfer of DsRed into the ganglionic eminence (GE) of a mouse embryo. Cortical interneurons show a diverse mode of migration. In coronal slices, ventrolateral-to-dorsomedial migration predominantly occurs in the lower-intermediate zone. However, a substantial number of interneurons migrate radially either towards the pial or ventricular surface. There are also quiescent neurons. Observations of the marginal zone or the ventricular zone in flat-mounted cortex from the pial or the ventricular surface, respectively, revealed that the interneurons tangentially migrate in all directions. Medial GE-derived interneurons visualized by DsRed electroporation show similar migratory behaviours. Thus, final settlement of cortical interneurons in their destinations may be a result of successive migratory process of different modes wkhin the cortex.