Cerebral Cortex Advance Access published online on October 21, 2009
Cerebral Cortex, doi:10.1093/cercor/bhp203
Spinogenesis and Pruning from Early Visual Onset to Adulthood: An Intracellular Injection Study of Layer III Pyramidal Cells in the Ventral Visual Cortical Pathway of the Macaque Monkey
1 Centre for Cognitive Neuroscience, Sunshine Coast, Queensland 4562, Australia, 2 Graduate School of Frontier Biosciences, Osaka University, Toyonaka, Osaka 560-8531, Japan
Address correspondence to Dr Guy N. Elston, Centre for Cognitive Neuroscience, 60 Duke Road, Doonan, Sunshine Coast, Queensland 4562, Australia. Email: guyelston{at}yahoo.com.
Neocortical pyramidal cells are characterized by markedly different structure among cortical areas in the mature brain. In the ventral visual pathway of adult primates, pyramidal cells become increasingly more branched and more spinous with anterior progression through the primary (V1), second (V2), and fourth (V4) visual areas and cytoarchitectonic areas TEO and TE. It is not known how these regional specializations in neuron structure develop. Here, we report that the basal dendritic trees of layer III pyramidal cells in V1, V2, V4, TEO, and TE were characterized by unique growth profiles. Different numbers of spines were grown in the dendritic trees of cells among these cortical areas and then subsequently pruned. In V1, V2, and V4, more spines were pruned than grew resulting in a net decrease in the number of spines in the dendritic trees following the onset of visual experience. In TEO and TE, neurons grew more spines than they pruned from visual onset to adulthood. These data suggest that visual experience may influence neuronal maturation in different ways in different cortical areas.
Key Words: cortex dendrite development Hebbian rule spines spontaneous activity