Visual Association Cortex and Vision in Man: Pattern-Evoked Occipital Potentials in a Blind Boy

In a 6-year-old child who had been blind since the age of 2 years, occipital potentials of normal amplitude and waveform could be evoked not only by diffuse light flashes but also by alternating checkerboard and sinusoidal grating patterns of low spatial frequency. Computerized tomography demonstrated destruction of the occipital lobes except of the primary visual projection area. Thus, in man, destruction of visual association cortices may result in loss of vision with partial preservation of pattern-evoked occipital potentials.