Cutaneous and stick rabbit illusions in individuals with autism spectrum disorder

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.

No differences in implicit hand maps among different degrees of autistic traits

“…Based on these previous findings and the findings of the current study, we could assume that relatively lower levels of somatosensory and motor neural processes are involved in implicit body representations with proprioceptive sensation similarly across levels of autistic traits. This idea seems to be consistent with the evidence that no differences between people with and without the diagnosis of ASD for the occurrence of a tactile illusion (cutaneous rabbit illusion) (Wada et al, 2020), in which the primary somatosensory cortex (SI) is involved (Blankenburg et al, 2006).…”

“…The current study estimated the implicit hand map underlying position sense with proprioceptive sensation, where the processes of spatial localization of the body are mainly involved. In contrast, previous studies showing ASD-related characteristics in proprioceptive processing focused on the situations related to hand movements in the external space (Haswell et al, 2009), temporal order judgments on the hands with hands crossed (Wada et al, 2014), and illusory sensations in the external space with touch on the body surface (rubber hand illusion; Cascio, Foss-Feig, et al, 2012;Greenfield et al, 2015;Ide & Wada, 2017;Paton et al, 2012). These are clearly related to the processes of spatial localization of touch.…”

“…The smaller magnitudes of the rubber-hand illusion indicate that the proprioceptive sensation for the participant's own hand is more reliable for people diagnosed with ASD against the presentation of a visible rubber that affects the proprioceptive sensation of the invisible participant's hand. Taken together with the finding that people diagnosed with ASD rather have difficulty suppressing visual distractors in simple visuotactile attention tasks (Poole et al, 2018), these experimental findings suggest that individuals with ASD and those with higher autistic traits have a stronger dependency on their proprioceptive sensations (Haswell et al, 2009;Wada et al, 2014).…”

“…Implicit hand maps were estimated by a localization task with visual landmarks on a hand silhouette (Hidaka et al, 2020;Longo, Mancini, & Haggard, 2015) both for fingers and markers on the dorsum side of the hand surface (Hidaka et al, 2020;Longo, Mancini, & Haggard, 2015). Based on the idea that people with the diagnosis of ASD and those with higher autistic traits have a stronger dependency on proprioceptive sensation (Haswell et al, 2009;Wada et al, 2014) and that low-level perceptual and neural processes of proprioceptive sensation could be the origin of the distortions in implicit hand maps (Longo, 2022), we predicted that the distortions of implicit hand maps would be different with different degrees of autistic traits. Since there was no evidence to support any direction of differences, we could not make any predictions about the direction of differences.…”