Effects of early anosmia on two classes of granule cells in developing mouse olfactory bulbs.

Quantitative morphometric methods were used to examine the effects of early unilateral anosmia on two classes of granule cells in developing mouse olfactory bulbs. Volumetric results show that the internal granule cell layer in the deprived olfactory bulb is significantly smaller than the same layer in the experienced olfactory bulb. The major factor contributing to this retarded development is a selective loss of one class of interneurons; dark granule cell number is substantially reduced, while light granule cell number is not. This selective effect appears to be related to the time course of cell proliferation and differentiation and provides clues to the way early experience regulates neural development.