遮蔽表面知覚の時間的・空間的手掛かりと脳活動との関係 : fMRI研究(コミュニケーション支援及び一般)

概要

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We can readily perceive the unity of an object even when it is partially occluded (Amodal Completion). We explored brain activity that related to the completion. Visual stimuli consisted of a rotating wedge and two occluders whose spatial and temporal configurations were manipulated. In a standard session, the wedge rotated around a fixation point while two occluders were stable in the lower-left and upper-right visual fields. This periodic rotation of the wedge caused a traveling wave of neural activity to sweep across the cortex. First, we tested whether the occluded structure was represented topographically. Even when the wedge passed behind the occluders, the phase topography in early visual areas, especially in V1 and V2, was consisted with the wedge rotation as if the occluded segment of the wedge was interpolated. In contrast, no completion effect was observed when the occluders and an occluded segment of the wedge were removed. Next, we investigated whether the neural response to the obscured surface depended on the previous appearance of a whole object seen before occlusion. When not a whole but two divided wedges were displayed before occlusion, no significant response to the obscured surface was observed. Altogether, it is suggested that low-level visual areas play an important role for visual completion in both spatial and temporal context.
社団法人電子情報通信学会の論文
2006-05-22