The organization and postnatal development of the commissural projection of the rat somatic sensory cortex.

摘要: Anterograde and retrograde tracing experiments have been used to demonstrate the origin terminal distribution of commissural fibers in first somatosensory cortex (SI) rat. The originate from pyramidal cells all layers, but predominantly layers III V. terminate a series approximately vertical bands. In each these there are concentrations terminals extending inner portion molecular layer deep as well superficial part V, VI. Discrete bands reciprocally connected across midline give both regions projection patchy or “columnar” appearance. arise areas that lie between alongside aggregations granule distinguish SI No within IV themselves more ramifications may come overlie aggregations. A heterotopic contralateral second has observed is similar form homotopic SI. Many crossed corpus callosum by day birth underlying white matter do not enter cortical plate until at least third postnatal day. During week grow somewhat diffusely into maturing their topographic laminar pattern attains its adult characteristics end week. Commissural axons, thus, immature maturation cell seems precede ingrowth axons acquisition synapses.