Modulation of the complex spike activity of Purkinje cells in the cerebellar flocculus can convey not only visual signals but also nonvisual signals. The nonvisual complex spike modulation, which is readily observed with vestibular stimulation of the awake rabbit in darkness, is approximately in-phase with the concomitant simple spike modulation. This nonreciprocal relationship contrasts to the reciprocal relationship found when the rabbit is afforded vision.