RESUMEN
Event-related desynchronization and visual orientational behavior were examined in 2 autistic boys to determine if blockade of endogenous opioid activity facilitates cognitive processing at a cortical level. Before naltrexone, the boys showed no selective alpha blocking during exposure to either mother's pictures or white light. Unlike normals, they exhibited strong alpha band enhancement at temporocentral recording sites. Two hours after administering 0.5 mg/kg naltrexone, mother-as well as light-related alpha blocking appeared at occipital, occipitotemporal, and prefrontal sites. These effects were gone 24 h after dosing in one child, but persisted in the other. A parallel increase in visual pursuit in a social context was observed. These results affirm that autistic gaze aversion can be caused by excessive opioid activity interfering with corticothalamocortical processing of visual stimuli.