Decreased number of cells in the inferior olivary nucleus of the developing staggerer mouse.

Light-microscopic study and cell counts of the inferior olivary nucleus (ION) were performed in staggerer mutant mice and compared to those obtained in C57B16J controls. The main result is that 60% of the olivary cells are missing in 24-day-old mutants and that most of the deficit is already present on postnatal day 10. It has been previously shown that the staggerer gene exerts an intrinsic effect on the Purkinje cells. Whether cells of the inferior olive are, in addition to Purkinje cells, a primary site of gene action, or whether they are retrogradely affected by the cerebellar malformation, remains unknown from the present study.