Abstract
Introduction: Recent studies have demonstrated the possible involvement of alpha oscillation (8–13 Hz) in visual processing (Jensen et al., 2012), but its functional role remains unknown. Here we tested the hypothesis that interaction between visual areas is mediated by the intrinsic alpha rhythm. We utilized an illusory jitter perception called motion-induced spatial conflict (Arnold and Johnston, 2003) which is ideal to highlight the interaction between visual areas. In this illusion, a moving isoluminant border is placed in close proximity to moving luminance-defined borders. As the isoluminant borders are perceived to move slower than the luminance-defined borders, dissociation between motion-based and object-based position representations is created. Methods: In the first experiment, the perceived jitter frequency of individual participants was compared with their peak alpha frequency (PAF) during resting state. In the second experiment, we measured the change in PAF within individual participants, correlated with the change in perceived jitter frequency. In the third experiment, we performed source localization on the MEG data during the perception of illusory jitter to directly test the hypothesis. Results and Discussion: In the first experiment, we found a significant correlation between perceived jitter frequency and PAF during resting state. In the second experiment, PAF in the perceptually slower jitter trials was significantly lower than that in faster jitter trials. These results suggest that the perceived frequency of illusory jitter reflects not only the inter-subject but also intra-subject variation of PAF. In the third experiment, alpha power in IPL as well as the coherence between IPL and IT at the alpha frequency was found to significantly increase during perception of illusory jitter. These results support the idea that the dissociation between motion-based delayed position representation in the dorsal stream and the object-based accurate position representation are resolved at the intrinsic alpha frequency.
Meeting abstract presented at VSS 2016