Cutaneous and stick rabbit illusions in individuals with autism spectrum disorder

Makoto Wada,Reiko Fukatsu,Misako Sano,Mayuko Suzuki,Hiromi Agarie,Kengo Nishimaki,Yasoichi Nakajima,Masakazu Ide,Sooyung Kim,Ari Tanaka,Seiki Tajima,Hanako Ikeda,Makoto Miyazaki

doi:10.1038/s41598-020-58536-z

Abstract

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. The prediction and postdiction are suggested to be similar based on theoretical models. Previous studies suggest that prediction is impaired in individuals with autism spectrum disorder (ASD). However, it is unclear whether postdiction is also impaired 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. We observed significant cutaneous and stick rabbit illusion in both typically developing (TD) and ASD groups; therefore, postdiction was functional in individuals with ASD. Our present results suggest that postdiction involves a different neuronal process than prediction. 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. We discuss implications of the individual difference among the ASD participants in the context of sports requiring interactions between the body and external objects.

Highlights

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
The results of the present study demonstrated that a considerable degree of the cutaneous and stick rabbit illusions was observed in the trials with shorter significant main effect for P1 deviations (SOA) both in the autism spectrum disorder (ASD) and typically developing (TD) groups
Our results indicated that postdiction remained functional in participants with ASD, at least in both, Arm and Stick conditions using tactile stimulation

Summary

Introduction

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. Previous studies suggest that prediction is impaired in individuals with autism spectrum disorder (ASD) It is unclear whether postdiction is impaired in individuals with ASD. 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. along the stick; stick rabbit illusion) This finding suggests that the cutaneous rabbit illusion involves an intrinsic somatotopic representation, and a representation of the extended body schema that results from body–object interactions[15,16]

Methods

Results

Conclusion