Visual function in the newborn infant: is it cortically mediated?

Reasonably normal visual behaviour was observed in premature infants in the neonatal period up to about 48 weeks' postmenstrual age even when there was gross destruction of the cortex in the occipital region. Symmetrical visual evoked responses could be elicited at this time even when asymmetrical lesions of the occipital cortex had been demonstrated on ultrasound scan; the visual evoked response became asymmetrical later, around the age of 2 months. A visual evoked response, albeit of abnormal waveform, was recorded in an infant with complete absence of the visual cortex. These findings suggest that early visual function, both behavioural and electrophysiological, is not dependent on the cortex but appears to be mediated through subcortical pathways.