| Autor: |
Anderson, S.A., Classey, J.D., Condé, F., Lund, J.S., Lewis, D.A. |
| Zdroj: |
Neuroscience; July 1995, Vol. 67 Issue: 1 p7-22, 16p |
| Abstrakt: |
Postnatal development of the primate cerebral cortex involves an initial proliferation and the subsequent attrition of cortical synapses. Although these maturational changes in synaptic density have been observed across the cortical mantle, little is known about the precise time course of developmental refinements in synaptic inputs to specific populations of cortical neurons. We examined the postnatal development of two markers of excitatory and inhibitory inputs to a subpopulation of layer III pyramidal neurons in areas 9 and 46 of rhesus monkey prefrontal cortex. These neurons are of particular interest because they play a major role in the flow of information both within and between cortical regions. Quantitative reconstructions of Golgi-impregnated mid-layer III pyramidal neurons revealed substantial developmental changes in the relative density of dendritic spines, the major site of excitatory inputs to these neurons. Relative spine density on both the apical and basilar dendritic trees increased by 50% during the first two postnatal months, remained at a plateau through 1.5 years of age, and then decreased over the peripubertal age range until stable adult levels were achieved. As a measure of the postnatal changes in inhibitory input to the axon initial segment of these pyramidal neurons, we determined the density of parvalbumin-immunoreactive axon terminals belonging to the chandelier class of local circuit neurons. The density of these distinctive axon terminals (cartridges) exhibited a temporal pattern of change that exactly paralleled the changes in dendritic spine density. |
| Databáze: |
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