perceptual extinction
an effect of lesions in the parieto-occipital region of the brain in which a stimulus, usually tactual or visual, is not detected. If a single stimulus is presented on either side of the midline, it is detected; however, when two stimuli are presented at the same time, one on each side of the midline, the stimulus on the side of the body opposite the location of the lesion is not detected. This phenomenon is utilized in neuropsychological research on attention mechanisms. Also called sensory extinction; sensory inattention.