Abstract
Previous work on implicit working memory suggested that we can unconsciously extract the pattern of sequentially presented visual stimuli and predict a subsequent stimulus (Hassin et al., 2009). Here we examined how unconsciously predicted visual stimuli are represented in early visual areas. On each trial, when a grating was presented in one of four differently sized annuli, participants determined the orientation of a tilted bar at the center of the screen. Four gratings were presented sequentially one in each annulus, from outermost to innermost. In each presentation, the grating’s orientation of was rotated by 30 degrees clockwise or counter-clockwise (continuous condition) or alternated between the two directions (discontinuous condition). In the regular pattern condition, the gratings were rotated following the predetermined rule; in the broken pattern condition, the fourth grating was rotated in the opposite of the predicted direction. As the participants’ attention was drawn to the stimulus at the center throughout the trial, they were not aware of the changing grating pattern in the periphery. Using fMRI and inverted encoding models, we reconstructed population-level, orientation-selective responses to sequentially presented gratings in early visual cortices. We found that orientation-selective response in extrastriate areas (V2 and V3) elicited by the fourth grating were stronger in the regular pattern condition than in the broken pattern condition when the grating’s orientation changed alternately between the two directions. However, the orientation response to the fourth grating did not differ between the regular and broken conditions when the grating’s orientation changed continuously in one direction. These results suggest that unconscious predictions formed by implicit working memory could alter information processing in early visual area.