Abstract
The perception of a moving object depends on the neural integration of form and motion information over space and time. Form and motion perception have historically been considered independent processes; however, research demonstrates that these processes interact in various and complex ways. Spatiotemporal form integration describes the process by which the visual system is able to integrate information about the shape of an object over space and time to form percepts that can mutually support both form and motion perception. A revealing example of this is the perception of static illusory figures generated by sequentially presented inducers. Here, we demonstrate that this type of spatiotemporal form integration can also lead to percepts of moving figures. This motion percept arises in the absence of any correlated motion energy in the image. We use fMRI to identify the neural correlates of spatiotemporal form integration in the context of object and motion perception. In a block design, inducers were flashed sequentially in each block to generate one of four experimental conditions: a static or moving illusory square percept, or a static or moving percept with no illusory square. Univariate GLM analyses of BOLD signals reveal that V3, V3AB, V4v and LOC preferentially respond when an illusory figure is present independently of whether or not it is moving. Additionally, visual areas hMT+ and KO show selective processing of the moving figure. Multivariate pattern analyses support these findings and also reveal that spatiotemporal form integration operates in a hierarchical fashion across visual areas. We conclude that the visual system can retain and update local and global form information over space and time leading to percepts of stationary, as well as moving objects. Furthermore, spatiotemporal form integration is mediated at least in part by mechanisms within specific regions of retinotopically organized visual cortex.
Meeting abstract presented at VSS 2012