Development of the main efferent cells of the olfactory bulb and of the bulbar component of the anterior commissure

Abstract

The development of the efferent cells of the main olfactory bulb and the development of the bulbar part of the anterior commissure were studied in the rat from E16 to P7. DiI was used in fixed tissues as a neuronal tracer. From E16 onwards cells located in the olfactory bulb anlage were stained in a Golgi-like appearance. The morphological changes of these cells were: from E16 to P4, re-orientation from a tangential position to a radial position, elongation of the principal dendrite and spreading out of the secondary dendrites. From P4 onwards, there was a lack of migrating mitral cells in the inner part of the bulb. At E16 some fibers of the anterior commissure reached the midline, the number of fibers increased slowly until P0/P1. At P2 there was an explosive increase in the number of fibers crossing the midline and reaching the contralateral bulb. The development in two stages is hypothesized.