Growth and targeting of subplate axons and establishment of major cortical pathways [published erratum appears in J Neurosci 1993 Mar;13(3):following table of contents]

摘要: In the developing mammalian neocortex, first postmitotic neurons form "preplate" superficial to neuroepithelium. The preplate is later split into a marginal zone (layer 1) and subplate by cortical plate that layers 2-6. Cortical efferent axons from 5 6 afferent thalamus pass between cortex subcortical structures through internal capsule. Here, we identify in rats axonal populations establish capsule, characterize potential role of development projections. early growth was studied using 1-1'-dioctodecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (Dil) as an anterograde retrograde tracer aldehyde-fixed brains embryonic rats. enter nascent capsule on day (E) 14 originate lateral anterior cortex; posterior extend rostrally but do not yet exit cortex. labeled axons, tipped cones with complex morphologies, take pathway deep preplate. Preplate these efferents, based developmental stage cortex, their location morphology. Most cells occupy subplate. E16. En route same path earlier-growing intermediate Subplate reach E16; about later. Thalamic E16, prior other afferents. On E15, both thalamic midpoint To determine distribution used Dil fast blue rhodamine-B-isothiocyanate vivo markers neonatal Tracers were injected superior colliculus, principal midbrain target layer neurons, at times before, during, after arrival or primary two points, cerebral peduncle caudal pyramidal decussation junction hindbrain spinal cord, shortly passing axons. every case, are confined 5; labeled.(ABSTRACT TRUNCATED AT 400 WORDS)