an impact of lesions in the parieto-occipital area on one side of the brain wherein a stimulant, generally visual or tactual, isn't noticed. If a sole stimulant appeared on either side of the midline, it is noticed- but, whenever two alike stimulants appear simultaneously, one on each side of the midline, the stimulant on the side of the body converse to the locale of the lesion isn't noticed. This phenomenon is utilized in neuropsychological research on attention mechanisms.
