Auditory specificity in unit recordings from cat's visual cortex

A substantial percentage of cells in the primary visual cortex of the cat can be activated by nonvisual stimuli. Twenty-five cells were studied in detail in five cats and their responses to visual and acoustic stimuli tested. While all units could be activated by visual stimuli, seven of these responded to visual and acoustic stimulation. Analysis with frequency-modulated tones showed that these seven units were responsive to specific parameters of the sound stimuli. Twodimensional maps done with a small disc on a contrasting background showed that these units have, in addition, visual receptive fields.