Ide Masakazu, Wada Makoto
Developmental Disorders Section, Department of Rehabilitation for Brain Functions, Research Institute of National Rehabilitation Center for Persons with DisabilitiesSaitama, Japan; Japan Society for the Promotion of ScienceTokyo, Japan.
Developmental Disorders Section, Department of Rehabilitation for Brain Functions, Research Institute of National Rehabilitation Center for Persons with Disabilities Saitama, Japan.
Front Integr Neurosci. 2016 Jun 9;10:21. doi: 10.3389/fnint.2016.00021. eCollection 2016.
In a rubber hand illusion (RHI) task, synchronous brush stroking of a rubber hand and a participant's hidden hand induces body ownership of the rubber hand. The effects of spatial distances and temporal lags on the RHI have been extensively examined; however, the effect of periodicity of the stimuli on illusory body ownership has not been examined. Meanwhile, the occurrence of RHI tends to be weak in individuals with autism-spectrum disorders (ASD) and high autistic traits. Preference for stimulus having regularity of tempo is generally observed in individuals with ASD, and thus, periodic stimulation might be more effective to elicit the body ownership illusion in individuals with high autistic traits. Hence, we investigated whether stimulus periodicity influenced RHI as well as its association with participant's autistic traits. Brush strokes were applied to a participant's own hand and the rubber hand periodically (2 s) or non-periodically (1-3 s), either synchronously or asynchronously. Two blocks were performed in each condition. We found that periodic stimulation enhanced the spatial updating of tactile sensation induced by RHI in the subsequent block in participants with high autistic traits, whereas both periodic and non-periodic stimulation strongly elicited RHI in blocks 1 and 2. These results indicate that the periodicity of stimulation has different effects based on an individual's autistic traits. Since individuals with ASD are known to sustain their focus on interoceptive sensations (heartbeats), a periodic stimulation that is potentially correlated with heartbeats might be effective to enhance the visuotactile integration during RHI in individuals with high autistic traits.
在橡皮手错觉（RHI）任务中，对橡皮手和参与者隐藏的手进行同步刷动会引发对橡皮手的身体所有权感。空间距离和时间延迟对橡皮手错觉的影响已得到广泛研究；然而，刺激的周期性对错觉性身体所有权的影响尚未得到研究。同时，自闭症谱系障碍（ASD）患者和高自闭症特征个体中橡皮手错觉的发生率往往较低。ASD患者通常表现出对具有节奏规律性刺激的偏好，因此，周期性刺激可能对引发高自闭症特征个体的身体所有权错觉更有效。因此，我们研究了刺激的周期性是否会影响橡皮手错觉以及它与参与者自闭症特征的关联。以周期性（2秒）或非周期性（1 - 3秒）的方式对参与者自己的手和橡皮手进行刷动，刷动可以是同步的或异步的。每种条件下进行两个实验块。我们发现，周期性刺激增强了高自闭症特征参与者在后续实验块中由橡皮手错觉诱发的触觉空间更新，而周期性和非周期性刺激在实验块1和实验块2中都强烈引发了橡皮手错觉。这些结果表明，刺激的周期性根据个体的自闭症特征有不同的影响。由于已知ASD患者会持续关注内感受觉（心跳），一种可能与心跳相关的周期性刺激可能有效地增强高自闭症特征个体在橡皮手错觉过程中的视觉触觉整合。
