Responsiveness of Clare-Bishop (CB) neurons to movement of a visual stimulus and to changes in stimulus disparity and size that associated with movements in depth were studied by using a three dimensional visual stimulator. (1) About a half of them (28/54) were sensitive to disparity- and size-stimuli. (2) the other half (20/54) were activated only by movement-stimulus, and (3) the remaining minority (6/54) responded equally well to all types of stimuli. These observations suggest that CB neurons encode movements in three dimensional space on the basis of their responsiveness to stimulus disparity and size.