Hierarchical development in macaque visual cortex
小賀智文、Guy N. Elston、藤田一郎
Spinogenesis and synaptic pruning during development via Hebbian-type reinforcement are widely believed to subserve connectional specificity. The magnitude and timing of spinogenesis and pruning in the cerebral cortex remain controversial. Here we studied pyramidal cells (n = 369) in macaque monkeys (Macaca fascicularis) to determine their synaptogenic profiles during development (2 days to 4.5 years old). Synaptogenic profiles of pyramidal cells in the primary visual area (V1) were compared with those in visual association area TE. Neurons were injected individually with Lucifer yellow in fixed cortical slices and processed for a DAB product. We found exuberant spinogenesis and pruning in the dendritic trees of pyramidal cells in both V1 and TE. However the timing and magnitude
differed considerably between groups. These data support the theory of a hierarchical developmental timecourse of synaptogenesis in the cerebral cortex.