Opsoclonus-induced occipital deactivation with a region-specific distribution.

The cerebral distribution of 2-[18F]fluoro 2-deoxy-D-glucose (FDG) uptake in a patient with opsoclonus was measured by positron emission tomography (PET) and subsequently compared with the distribution in ten normal subjects. Statistical parametric mapping (SPM) revealed a decreased occipital FDG uptake in the patient, particularly at the posterior bank of the parieto-occipital sulcus (putative visual area PO/V6), in the region ventrally bordering V5, and anterolaterally in the calcarine sulcus. Such a specific pattern of occipital deactivation may indicate that opsoclonus suppresses the processing of visual motion along the magnocellular pathway. This is in agreement with normal saccadic suppression which has been proposed to contribute to the perception of a stable visual space.