Unanesthetized Long-Evans (pigmented) rats were subjected to 2.0 G centripetal acceleration for 90 min. Immunohistochemical analysis, using a polyclonal antibody for Fos, revealed a distinct pattern of neuronal activation in the off-axis animals in the dorsomedial cell column (DMCC) of the inferior olivary nucleus. These results are consistent with previous anatomical evidence and indicate that the DMCC is an important component in an otolith-olivocerebellar circuit which may help to define an internal spatial reference.