Hidaka Souta, Tucciarelli Raffaele, Azañón Elena, Longo Matthew R
Department of Psychology, Rikkyo University, 1-2-26, Kitano, Niiza-shi, Saitama 352-8558, Japan; Department of Psychological Sciences, Birkbeck, University of London, United Kingdom.
Department of Psychological Sciences, Birkbeck, University of London, United Kingdom.
Acta Psychol (Amst). 2020 Jul;208:103090. doi: 10.1016/j.actpsy.2020.103090. Epub 2020 May 30.
Recent studies have demonstrated that mental representations of the hand dorsum are distorted even for healthy participants. Perceptual hand maps estimated by pointing to specific landmarks (e.g., knuckles and tips of fingers) is stretched and shrunk along the medio-lateral and the proximo-distal axes, respectively. Similarly, tactile distance perception between two touches is longer along the medio-lateral axis than the proximo-distal axis. The congruency of the two types of distortions suggests that common perceptual and neural representations may be involved in these processes. Prolonged stimulation by two simultaneous touches having a particular distance can bias subsequent perception of tactile distances (e.g., adaptation to a long distance induces shorter stimuli to be perceived even shorter). This tactile distance adaptation aftereffect has been suggested to occur based on the modulations of perceptual and neural responses at low somatosensory processing stages. The current study investigated whether tactile distance adaptation aftereffects affect also the pattern of distortions on the perceptual hand maps. Participants localized locations on the hand dorsum cued by tactile stimulations (Experiment 1) or visually presented landmarks on a hand silhouette (Experiment 2). Each trial was preceded by adaptation to either a small (2 cm) or large (4 cm) tactile distance. We found clear tactile distance aftereffects. However, no changes were observed for the distorted pattern of the perceptual hand maps following adaptation to a tactile distance. Our results showed that internal body representations involved in perceptual distortions may be distinct between tactile distance perception and the perceptual hand maps underlying position sense.
最近的研究表明，即使对于健康参与者，手背的心理表征也会出现扭曲。通过指向特定地标（如指关节和指尖）估计的感知手部地图分别沿中外侧轴和近远侧轴拉伸和收缩。同样，两次触摸之间的触觉距离感知在中外侧轴上比在近远侧轴上更长。这两种类型扭曲的一致性表明，共同的感知和神经表征可能参与了这些过程。由具有特定距离的两次同时触摸产生的长时间刺激会使随后的触觉距离感知产生偏差（例如，适应远距离会使较短的刺激被感知得更短）。有人认为这种触觉距离适应后效是基于低体感处理阶段感知和神经反应的调制而发生的。当前的研究调查了触觉距离适应后效是否也会影响感知手部地图上的扭曲模式。参与者通过触觉刺激（实验1）或手部轮廓上视觉呈现的地标（实验2）来定位手背上的位置。每次试验之前先适应小（2厘米）或大（4厘米）的触觉距离。我们发现了明显的触觉距离后效。然而，在适应触觉距离后，感知手部地图的扭曲模式没有观察到变化。我们的结果表明，参与感知扭曲的内部身体表征在触觉距离感知和位置感所基于的感知手部地图之间可能是不同的。
