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Terminal arborizations of olfactory nerve fibers in the glomeruli of the olfactory bulb
Author(s) -
Hálasz Norbert,
Greer Charles A.
Publication year - 1993
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.903370211
Subject(s) - olfactory bulb , glomerulus , biology , olfactory system , olfactory nerve , olfactory epithelium , anatomy , odor , neuroscience , afferent , context (archaeology) , bulb , axon , terminal nerve , olfactory receptor , central nervous system , endocrinology , botany , paleontology , kidney , hormone
The glomerulus of the olfactory bulb may serve as a fundamental organizational unit for odor representation. In this context, the axons of olfactory receptor cells with similar response spectra may converge in specific glomerlui. While the topography between the olfactory epithelium and the olfactory bulb glomeruli has been explored, the characteristics of primary afferent terminal fields within glomeruli are poorly understood. To explore this issue, reconstructions of the terminal arbors of single olfactory nerve (ON) fibers within glomeruli were carried out in the rat olfactory bulb at the light microscopic level. Tissue samples prepared with the Golgi‐EM technique resulted in distinct impregnation of limited subsets of individual ON fibers. Following camera lucida reconstruction, quantitative analyses were made on selected sets of ON fibers and on the glomeruli they invaded. Most ON fibers began to arborize only after penetrating the glomeruli to a mean depth of approximately 35.9 μm. The fibers gave rise to a complex arbor of branches that was limited in total length (mean 157.7 μm) and the number of en passant varicosities or terminal enlargements (mean = 8.1). The number of varicosities and terminal boutons was proportional to the total length of branches. Also, there was a statistically significant correlation between the total branch length and the area (μm 2 ) encompassed by the total arbor. The intraglomerular region supplied by the terminal arbor of an individual ON fiber was generally restricted. Given the recent molecular specificity attributed to olfactory receptor cells, this may provide a morphological basis for selective processing of signals encoded by specific receptors in the olfactory epithelium. © 1993 Wiley‐Liss, Inc.