Deficits in the visual evoked potentials of cats as a result of visual deprivation

Visual evoked potentials in response to contrast reversal of grating patterns were used as a measure of visual function in normal and visually deprived cats. In cats which had been dark reared from birth (BD cats) there was a characteristic change in VEP waveform from normal, for both eyes and for all spatial frequencies of testing stimulus. In cats which had one eye sutured from the age of one week (MD cats), the VEP from the deprived eye was smaller for contrast reversal of coarse patterns. Kittens given only restricted periods of monocular exposure gave VEPs which resembled the pathological responses of the BD cats. However, the amplitudes of response were larger for the more experienced eye at higher spatial frequency. This work reinforces the idea that two factors govern cortical development: competition and experience. Lack of sufficient visual experience leads to severe intracortical pathology.