Moving one's own body part induces a motion aftereffect anchored to the body part

The question of how our body parts successfully interact with objects in the outside world is a fundamental problem in cognitive science and neuroscience [1, 2]. This problem is closely related to biologically important behaviors such as avoiding collisions or safely reaching for an object [3]. Although previous studies have suggested that perceiving the space around one's own body is essential for interacting successfully with objects [4, 5], how one's own body parts influence the ability to perceive the space around the body is unknown. Here, we report a visual motion aftereffect (MAE) that shows spatial selectivity in hand-centered coordinates. The MAE is an illusion of visual motion resulting from adaptation to a moving pattern and normally occurs with retinal overlap between adaptor and test [6]. We found that the MAE occurs without retinal overlap between the adaptor and test when they are presented at the same position relative to a seen hand. This MAE appeared only when participants voluntarily controlled the hand that was felt to be their own. Our results reveal that sense of owning an actively moved body part generates a perceptual representation of the space encoded in body-part-centered coordinates that might be useful for guiding movements of one's body parts.