Staffordshire ST5 5BG Brisk sustained and brisk transient retinal ganglion cells in cat are not differentially sensitive to motion of static visual noise (texture) (Ahmed, 1981). The present report considers the spatial extent of their response to texture motion.Recordings were obtained from single optic tract fibres in cats lightly anaesthetized with 75 % :25 % N20 :02 supplemented with pentobarbitone. E.e.g, and e.c.g and heart rate, end-tidal CO2 and rectal temperature were continuously monitored. A texture field, electronically generated on a CRT display, was moved back and forth at 60. sec' within a stationary 100 by 100 frame. The texture field could be masked by discs (matt white), or confined by a circular window, 10 to 80 in diameter, centred on the receptive field. Peristimulus time histograms for texture motion were compared under the masked, window and whole texture-field conditions. The data show that the magnitude of response-modulation of brisk sustained and brisk transient retinal ganglion cells is dependent upon interactions spatially limited to the region of the classically-defined receptive field of the cell. The strongest response-modulation was obtained for the window condition, where texture motion primarily influenced the centre mechanism of the cell's receptive field. As the window was increased in diameter, encroaching progressively into the receptive field surround, the response-modulation decreased towards the level obtained with whole texture-field motion. The response in the masking condition (primarily surround stimulation) was dependent upon the spatial extent of the mask, and consisted of a weak modulation or no change in the maintained activity.In conclusion, the response of retinal ganglion cells to texture motion is confined spatially to interactions between the centre and the antagonistic surround of the receptive field.