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Postnatal development of dendritic spines on olfactory bulb granule cells in rats
Author(s) -
Matsutani Shinji,
Yamamoto Noboru
Publication year - 2004
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.20107
Subject(s) - filopodia , dendritic filopodia , olfactory bulb , biology , granule cell , dendritic spine , microbiology and biotechnology , neurogenesis , anatomy , granule (geology) , olfactory system , neuroscience , central nervous system , hippocampal formation , actin , paleontology , dentate gyrus
Postnatal morphological changes in granule cell dendritic spines and filopodia (collectively referred to as “spines/filopodia”) were examined in the rat main olfactory bulb to characterize the development of the neural circuitry for olfaction. Granule cells were labeled with a membrane dye and confocal laser scanning microscope images of labeled spines/filopodia were acquired in the following three dendritic domains: apical dendrites in the external plexiform layer, those in the granule cell layer, and basal dendrites. In all three domains the proportion of typical spines slightly increased during development, with a concomitant decrease in the proportion of “stubby” spines lacking a neck; the proportion of filopodia remained unchanged, accounting for 20–40% of all protrusions. The mean diameter and length of the spine/filopodium population were nearly constant throughout development. On the other hand, the developmental pattern of the spine/filopodium density varied markedly, depending on the domain of the dendrites. In the external plexiform layer, the density did not change remarkably during development. The density in apical dendrites in the granule cell layer increased during the initial 2 postnatal weeks, then gradually decreased. The spine/filopodium density in basal dendrites, however, continued to increase until 4 weeks of age, and then began to decrease. These results suggest that a substantial amount of input‐specific synaptic remodeling occurs in granule cells during development, which proceeds from superficial dendritic domains to deeper ones, occurring most prominently in the basal dendrites. J. Comp. Neurol. 473:553–561, 2004. © 2004 Wiley‐Liss, Inc.