Psychophysical and cognitive brain scientific approach to the stabilization of perceptual world

The present study investigated the mechanism stabilizing our perceptual world by behavioral and cognitive neuroscientific approaches. As an example of the stabilizing mechanism, we can point to the reduction of stimulus visibility caused by its motion and the surround suppression around the focus of attention. First, we focused on object substitution masking (OSM : Di Lollo, Enns, & Rensink, 2000) because information update accompanying perception of target-mask continuity and inhibitory surrounds triggered by remaining masks are thought to be involved in substitution masking. Behavioral experiments showed that an illusory object induced by subjective contours reduced the visibility of the target when persisting beyond its offset in its immediate vicinity and that asymmetric OSM discovered by Jiang and Chun (2001) occurs relative to the direction of attentional shift irrespective of the central-peripheral relation between the target and mask. Attentional selection of relevant events and attentional inhibition of irrelevant events are also crucial to the stabilization of perceptual world. In order to elucidate the selective attention mechanism, we searched for the neural correlates of top-down attentional control by functional magnetic resonance imaging and investigated the brain mechanism of attentional blink (AB : Raymond, Sharpiro, & Arnell, 1992) by transcranial magnetic stimulation.As a result, it is suggested that top-down attentional control is implemented by the right intraparietal sulcus efficiently modulating occipital visual areas and enhancing their activations and that the intraparietal sulcus is associated with an attentional set for respective targets and the inferior parietal lobule is involved in the disengagement and reorienting of attention from the first target to the second target in AB.