| Popis: |
When a static stimulus appears successively at two different locations, we perceive a transition of the stimulus across them—apparent motion. Previous studies have shown that some spatio-temporal representation is reconstructed in the apparent motion path and it leads to increased activation in the region of the primary visual cortex (V1) corresponding to the apparent motion path (Muckli et al., 2005 PLoS Biology 3 1501–1510). However, little is known about whether visual properties of an object engaged in apparent motion are maintained in this representation. In order to address this question, we used fMRI and pattern classification methods to examine the neural representation created on the apparent motion path when the object changes its orientation across the apparent motion path. Two intermediate orientations (0° and 90°) on the apparent motion path were induced by presenting gratings with different orientations at separate locations. The gratings were presented in a bistable quartet sequence, and subjects were instructed to perceive either vertical or horizontal direction of motion during each trial. The results show that the regions of V1 contain information of the intermediate representations (0° vs. 90°) between the two gratings when they correspond to the path of perceived rotation but not when they are no longer on the motion path. This suggests that V1 generates neural representation of visual features that do not exist in the physical stimulus, but that correspond to our conscious perceptual experience of dynamic visual objects. |
