Abnormal connectivity of the visual pathways in human albinos demonstrated by susceptibility-sensitized MRI.

We studied activation of the human visual cortex (VC) using susceptibility-sensitized MRI at 1.5 Tesla. Three albinos and six healthy controls underwent a series of monocular and binocular photic flash stimulation. Monocular stimulation in albinos caused predominant contralateral activation with a small, well-delineated area in the anterior part of the VC in the ipsilateral hemisphere. This finding was consistent with a chiasmal crossing anomaly in albinism. All controls had symmetric patterns of activation during monocular stimulation. Functional MRI represents a promising method for evaluation of the visual pathways in humans.