Occipital lobe morphology in normal individuals assessed by magnetic resonance imaging (MRI).

The topography of visual evoked potentials (VEP) is dependent on occipital lobe morphology. Using magnetic resonance imaging we examine the sulcal pattern (the calcarine and parieto-occipital sulci), and assess the size of the cuneus and the asymmetry of the occipital lobes, computed separately for its ventral and dorsal segments. No differences were found for either the cuneus or the sulci pattern. In contrast, hemispheric asymmetry values appeared to be substantial. The predominance of the left occipital area was seen distinctly in the ventro-caudal portion of the occipital lobe. It was frequently reversed in the dorsal aspect of the lobe, notably in more rostral cuts. Such complexities may lead to ambiguities in interpreting VEP asymmetries.