Department of Psychology, Chiba University Chiba, Japan.
Front Psychol. 2012 Oct 22;3:427. doi: 10.3389/fpsyg.2012.00427. eCollection 2012.
Our somatosensory system deals with not only spatial but also temporal imprecision, resulting in characteristic spatiotemporal illusions. Repeated rapid stimulation at the wrist, then near the elbow, can create the illusion of touch at intervening locations along the arm (as if a rabbit is hopping along the arm). This is known as the "cutaneous rabbit effect" (CRE). Previous studies have suggested that the CRE involves not only an intrinsic somatotopic representation but also the representation of an extended body schema that includes causality or animacy perception upon the skin. On the other hand, unlike other multi-modal causality couplings, it is possible that the CRE is not affected by concurrent auditory temporal information. The present study examined the effect of a simple visual flash on the CRE, which has both temporal and spatial information. Here, stronger cross-modal causality or correspondence could be provided. We presented three successive tactile stimuli on the inside of a participant's left arm. Stimuli were presented on the wrist, elbow, and midway between the two. Results from our five experimental manipulations suggest that a one-shot flash enhances or attenuates the CRE depending on its congruency with cutaneous rabbit saltation. Our results reflect that (1) our brain interprets successive stimuli on the skin as motion in terms of time and space (unimodal causality) and that (2) the concurrent signals from other modalities provide clues for creating unified representations of this external motion (multi-modal causality) as to the extent that "spatiotemporal" synchronicity among modalities is provided.
我们的躯体感觉系统不仅处理空间上的不准确性,还处理时间上的不准确性,从而产生特征性的时空错觉。在手腕处反复快速刺激,然后在肘部附近刺激,可以在手臂的中间位置产生触觉的错觉(就好像一只兔子沿着手臂跳跃)。这被称为“皮肤兔子效应”(CRE)。先前的研究表明,CRE 不仅涉及内在的躯体感觉代表,还涉及扩展的身体图式的代表,包括对皮肤的因果关系或生命感知。另一方面,与其他多模态因果关系耦合不同,CRE 可能不受同时的听觉时间信息的影响。本研究考察了具有时间和空间信息的简单视觉闪光对 CRE 的影响。在这里,可以提供更强的跨模态因果关系或对应关系。我们在参与者的左臂内侧呈现三个连续的触觉刺激。刺激分别在手腕、肘部和两者之间呈现。我们五个实验操作的结果表明,单次闪光会根据其与皮肤兔子跳跃的一致性来增强或减弱 CRE。我们的结果反映出:(1)我们的大脑以时间和空间的方式将皮肤上的连续刺激解释为运动(单模态因果关系);(2)来自其他模态的同时信号为创建外部运动的统一表示提供了线索,因为模态之间的“时空”同步程度。