Abstract
Pyramidal cells grow and mature at different rates among different cortical areas in the macaque monkey. In particular, differences across the areas have been reported in both the timing and magnitude of growth, branching, spinogenesis, and pruning in the basal dendritic trees of cells in layer III. Presently available data suggest that these different growth profiles reflect the type of functions performed by these cells in the adult brain. However, to date, studies have focused on only a relatively few cortical areas. In the present investigation we quantified the growth of the dendritic trees of layer III pyramidal cells in the anterior ventral portion of cytoarchitectonic area TE (TEav) to better comprehend developmental trends in the cerebral cortex. We quantified the growth and branching of the dendrities, and spinogenesis and pruning of spines, from post-natal day 2 (PND2) to four and a half years of age. We found that the dendritic trees increase in size from PND2 to 7 months of age and thereafter became smaller. The dendritic trees became increasingly more branched from PND2 into adulthood. There was a two-fold increase in the number of spines in the basal dendritic trees of pyramidal cells from PND2 to 3.5 months of age and then a 10% net decrease in spine number into adulthood. Thus, the growth profile of layer III pyramidal cells in the anterior ventral portion of the inferotemporal cortex differs to that in other cortical areas associated with visual processing.
Highlights
While synaptogenesis peaks in the first few months after birth in the macaque monkey cerebral cortex (Rakic et al, 1986; Bourgeois et al, 1994), pyramidal cells in some cortical areas appear to continue to grow longer dendrites, increasing their dendritic territories, become more branched, and continue to grow spines over a period of years
We found that relative changes in the size of the basal dendritic trees of layer III pyramidal cells in TEav from post-natal day 2 (PND2) into adulthood differed from those in other cortical areas involved in visual processing, as did changes in branching structure
One hundred and six of these cells were included for analyses as they satisfied inclusion criteria (Table 1): namely, they (1) had an unambiguous apical dendrite, (2) had their complete basal dendritic trees contained within the section, and (3) were well filled
Summary
While synaptogenesis peaks in the first few months after birth in the macaque monkey cerebral cortex (Rakic et al, 1986; Bourgeois et al, 1994), pyramidal cells in some cortical areas appear to continue to grow longer dendrites, increasing their dendritic territories, become more branched, and continue to grow spines over a period of years. Protracted synaptogenesis and dendritic growth has been reported in prefrontal cortex in human (Huttenlocher, 1990; Huttenlocher and Dabholkar, 1997; Conel, 1967) Those in the primary visual area (V1) of the macaque monkey become progressively smaller from birth into adulthood, with as much as a 30% decrease in size of their dendritic trees during this time (Boothe et al, 1979; Elston et al, 2010a). We found that relative changes in the size of the basal dendritic trees of layer III pyramidal cells in TEav from post-natal day 2 (PND2) into adulthood differed from those in other cortical areas involved in visual processing, as did changes in branching structure. There was a two-fold increase in the number of spines in the basal dendritic trees of pyramidal cells from PND2 to 3.5 months of age and Frontiers in Neuroanatomy www.frontiersin.org
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
