In the rubber-hand illusion (RHI), when an actual hand hidden from view and a rubber hand in view are simultaneously stimulated, participants mistakenly perceive tactile sensation as arising from the rubber hand, not from the actual hand. Some studies have revealed that the magnitude of RHI decreases when the actual and rubber hand are incongruent in terms of hand angle. However, the acceptable range of angular deviations between the actual and rubber hand and its determination factor has not been investigated so far. I attempt to examine the angle-congruency effect between the actual and rubber hands on RHI. The left rubber hand simulated by 3-D computer graphics was rotated at 8 angles. Participants perceived higher ownership of the stimulated rubber hand when the angles were at 0 degrees, 45 degrees, 90 degrees, and 315 degrees (these are easy to mimic with the actual hand) than at 180 degrees, 225 degrees, and 270 degrees (these are difficult to mimic with the actual hand). The perceived location of the actual hand became closer to that of the simulated rubber hand with increased perception of ownership of the rubber hand. Moreover, the onset duration of RHI became shorter, especially for the angles of 0 degrees, 45 degrees, and 315 degrees. These results suggest that RHI occurs mainly within the range where people usually rotate their hand and that body representation might include the knowledge of "anatomical plausibility".

In a single modality, the percept of an input (e.g., voices of neighbors) is often suppressed by another (e.g., the sound of a car horn nearby) due to close interactions of neural responses to these inputs. Recent studies have also suggested that close interactions of neural responses could occur even across sensory modalities, especially for audio-visual interactions. However, direct behavioral evidence regarding the audio-visual perceptual suppression effect has not been reported in a study with humans. Here, we investigated whether sound could have a suppressive effect on visual perception. We found that white noise bursts presented through headphones degraded visual orientation discrimination performance. This auditory suppression effect on visual perception frequently occurred when these inputs were presented in a spatially and temporally consistent manner. These results indicate that the perceptual suppression effect could occur across auditory and visual modalities based on close and direct neural interactions among those sensory inputs.

The ownership of one's body parts represents a fundamental aspect of self-consciousness. Accumulating empirical evidence supports the existence of this concept in humans and nonhuman primates, but it is unclear whether nonprimate mammals experience similar feelings. Therefore, the present study used rubber tails to investigate body ownership in rodents. When the real tails and rubber tails were synchronously stroked, the mice responded as if their own tails were touched when the rubber tails were grasped. In contrast, when the stimuli were delivered asynchronously, there was a significantly lower mean response rate when the rubber tail was grasped. These findings suggest that mice may experience body ownership of their tails, suggestive of the rubber hand illusion in humans.

Many individuals with autism spectrum disorder (ASD) have symptoms of sensory hypersensitivity. Several studies have shown high individual variations in temporal processing of tactile stimuli. We hypothesized that these individual differences are linked to differences in hyper-reactivity among individuals with ASD. Participants performed two tasks as to vibrotactile stimuli: One is a temporal order judgement task, and another is a detection task. We found that individuals with ASD with higher temporal resolution tended to have more severe hypersensitivity symptoms. In contrast, the tactile detection threshold/sensitivity were related to the severities of stereotyped behaviour and restricted interests, rather than to hypersensitivity. Our findings demonstrate that higher temporal resolution to sensory stimuli may contribute to sensory hypersensitivity in individuals with ASD.