#FIND THE RABBIT ILLUSION SKIN#

In individuals with ASD who rely on intrinsic representations, the stick rabbit illusion that uses representations of the extended body schema in external space would be weakened or would even disappear, in cases where the cutaneous rabbit illusion itself remains intact. For example, in a motor learning task, such as a reaching task with disturbance by a robot arm, children with ASD rely relatively more on intrinsic coordinates (identical joint rotations as compared to the target) generated from proprioception, whereas typically developing (TD) children rely relatively more on extrinsic coordinates based on external space (identical hand motions as compared to the target) 3. Notably, previous studies have reported that individuals with ASD rely greatly on proprioception 3, 17. This finding suggests that the cutaneous rabbit illusion involves not only an intrinsic somatotopic representation, but also a representation of the extended body schema that results from body–object interactions 15, 16. When participants held a stick across the tips of their index fingers of both hands and successive taps were delivered to both index fingers via the stick, they reported feeling illusory taps in the space between the actual stimulus locations (i.e. 14 demonstrated that the cutaneous rabbit “hops out of the body”. If postdiction of sensory signals is impaired in individuals with ASD, the cutaneous rabbit illusion would not occur. This process by which the location of the taps is moved, following stimuli application is thought to reflect the postdictive perceptual process.

#FIND THE RABBIT ILLUSION SKIN#

In the cutaneous rabbit illusion, successive rapid taps are delivered first at one location on the skin and then at another, causing a participant to perceive illusory taps between the two locations at which the stimuli are actually delivered, as if a small rabbit hopped along the skin 12, 13. We speculated that postdiction, which shares a similar process to prediction, is also affected in individuals with ASD. a Bayesian perceptual model) 11, it remains unclear whether postdiction is impaired in individuals with ASD. Although prediction and postdiction are hypothesised to share similar processes (e.g. Sensory perception is influenced by both prediction and postdiction, the latter of which refers to the phenomenon in which perceptions of the previous sensory signal are influenced by subsequent signals 10. Taken together, these findings suggest that some of motor deficits in individuals with ASD were characterized by impairments in prediction (e.g., reduction of anticipatory behaviours).

For example, motor anticipation is reduced during postural control in children with ASD 6, 7, 8, whereas the anticipatory behaviour in which a baby opens his or her mouth in anticipation of a spoon’s approach has been impaired in infants later diagnosed with ASD 9. Previous studies have also indicated that autism is a disorder of prediction 4, 5.

In such individuals, atypical motor skills are highly associated with social and communicative deficits, which represent the core symptoms of ASD 2, 3. Individuals with autism spectrum disorder (ASD) exhibit a wide variety of motor deficits, such as impairments in imitation, motor coordination 1, 2, and tool use 1. We discuss implications of the individual difference among the ASD participants in the context of sports requiring interactions between the body and external objects.

We also observed that the ASD group exhibited significantly larger individual difference compared with the TD group in the stick rabbit illusion, which is considered to reflect extension of body schema to external objects. Our present results suggest that postdiction involves a different neuronal process than prediction. We observed significant cutaneous and stick rabbit illusion in both typically developing (TD) and ASD groups therefore, postdiction was functional in individuals with ASD. In this study, we evaluated postdiction in individuals with ASD using the cutaneous and stick rabbit illusion paradigms in which the perceived location of a touch shifts postdictively in response to a subsequent touch stimulus. However, it is unclear whether postdiction is also impaired in individuals with ASD. Previous studies suggest that prediction is impaired in individuals with autism spectrum disorder (ASD). The prediction and postdiction are suggested to be similar based on theoretical models. Prediction is the process by which future events are anticipated based on past events in contrast, postdiction is the retrospective interpretation of past events based on latter, more recent events.

Find the rabbit illusion