MAGNETIC-RESONANCE-IMAGING OF THE VISUAL PATHWAYS IN HUMAN ALBINOS

Neuroanatomical and electrophysiological studies of albino visual path ways have demonstrated that retinogeniculate axons arising from the te mporal retina decussate abnormally in the optic chiasm to synapse in t he contralateral lateral geniculate nucleus (LGN). Anomalies in the LG N secondarily disrupt normal geniculo-cortical and interhemispheric co rtico-cortical (callosal) visual connections. It is not known whether retinogeniculate misrouting affects the size or configuration of the a fferent visual pathways in human albinos. We used T1-weighted coronal and sagittal magnetic resonance imaging (MRI) to examine the prechiasm atic intracranial optic nerves, optic chiasm, and corpus callosum in 1 0 human albinos. In all subjects, these structures were normal in size and configuration. Despite the complex cascade of aberrant central ne uronal connections, the human albino visual pathways and their inter-h emispheric connections appear normal in size and configuration when vi ewed with MRI.