Purkinje cells in the vestibulocerebellum of the pigeon respond best to either translational or rotational wholefield visual motion.

Using standard extracellular techniques, the response properties of neurons in the vestibulocerebellum of the pigeon to movement of a wholefield visual stimulus were determined. Complex spike activity of Purkinje cells was modulated in a direction-selective manner by the stimulus and 94% of cells were binocularly driven. Some neurons preferred the same direction of wholefield motion in both eyes, simulating optic flow which results from self-translation, while others preferred the opposite direction in each eye, simulating optic flow resulting from rotation. Four functional classes of neurons were found: (1) Descent cells preferred upward motion in both eyes; (2) Ascent neurons preferred downward motion in both eyes; (3) Roll cells preferred upward and downward motion in the ipsilateral and contralateral eyes respectively; and (4) Yaw cells preferred forward (temporal to nasal) and backward motion in the ipsilateral and contralateral eyes respectively. The observation that these neurons clearly distinguish rotational and translational optic flow patterns suggest they may play an important role in controlling locomotor activities of the pigeon.