Single cells recorded from primary auditory cortex (AI and AII) of unanesthetized paralyzed cats were tested for responses to visual stimulation. Fortysix cells recorded from normal animals responded to acoustic stimuli but showed no discrete response to light flashes or small spots and bars. Twenty-two cells recorded from a congenitally deaf cat were spontaneously active but showed no discrete response to either auditory or visual stimulation. © 1970.