Abstract
While alpha oscillations modulate various aspects of visual processing, their functional roles in visual perception are unclear. Our previous study (Minami and Amano, VSS2016) showed a tight relationship between alpha oscillations and an illusory jitter, called the motion-induced spatial conflict (MISC; Arnold & Johston, 2005). The MISC is a phenomenon where moving borders defined by color contrast are perceived to be jittering when they are placed in close proximity with those defined by luminance contrast. This enables us to study the mechanisms underlying the interaction of motion and shape processing. To further understand the mechanisms of alpha oscillation involvement in illusory jitter perception, we examined the relationship between the characteristics of alpha oscillations and the functional/structural property of dorsal-ventral communication in the visual cortex. In the first experiment, MEG responses were measured during illusory jitter perception, and the changes in both alpha power and alpha coherence were estimated by a method called DICS (Gross et al., 2001). In the second experiment, diffusion magnetic resonance imaging (MRI) data were collected, and major white-matter tracts were reconstructed by probabilistic tractography. Then, the individual differences in fractional anisotropy (FA) of each tract and the peak alpha frequency (PAF) were compared. In the first experiment, alpha power in IPL as well as alpha coherence between IPL and IT were significantly increased during illusory jitter perception, suggesting the involvement of communication between the dorsal and ventral visual areas in illusory jitter. In the second experiment, the PAF was found to be significantly correlated with the FA in the left vertical occipital fasciculus (Yeatman et al., 2014), connecting dorsal and ventral visual areas. Correlations with other fibers were not significant. These results consistently indicate that the communication between the dorsal and ventral visual areas, which is highlighted by the MISC, is mediated by intrinsic alpha oscillations.
Meeting abstract presented at VSS 2017