ATTENTION-REGULATED ACTIVITY IN HUMAN PRIMARY VISUAL-CORTEX

Effects of attention to a local contour of a moving object on the acti vation of human primary visual cortex (area V1) were examined. Local c erebral oxygenation changes (an index of neuronal activity) in human a rea V1 were measured with functional magnetic resonance imaging (fMRI) in conditions including the following two: 1) when attention was sele ctively directed toward one side of a moving wedge (the attention cond ition) and 2) when the wedges were viewed passively (the passive condi tion). Activation in area V1 was found to be higher in the attention c ondition than in the passive condition. To our knowledge, this is the first finding that attention to motion activates as early as area V1. We suggest that attentional activation of area V1 is task dependent.