Watanabe Junji, Hayashi Seiichiro, Kajimoto Hiroyuki, Tachi Susumu, Nishida Shin'ya
PRESTO Japan Science and Technology Agency, 3-1, Morinosato-Wakamiya, Atsugi, Kanagawa, 243-0198, Japan.
Exp Brain Res. 2007 Jul;180(3):577-82. doi: 10.1007/s00221-007-0979-z. Epub 2007 Jun 5.
Tactile motion perception is one of the most important functions for realizing a delicate appreciation of the tactile world. To explore the neural dynamics of motion processing in the brain, the motion adaptation phenomenon can be a useful probe. Tactile motion aftereffects (MAE), however, have not been reported in a reproducible fashion, and the indistinctive outcomes of the previous studies can be ascribed to the non-optimal choice of adapting and testing stimuli. Considering the features of the stimuli used in the studies, the stimuli activated the different mechanoreceptors in the adapting and testing phase. Consequently, we tested tactile MAE using appropriate combinations of adapting and testing stimuli. We used three pins to generate sensation of apparent motion on the finger cushion. They were sequentially vibrated with the frequency of 30 Hz both in adapting and testing phases. It is expected that this procedure ensured stimulation for the same mechanoreceptor (Rapid-Adapting mechanoreceptor) in both the adaptation and test phases. Using this procedure, we found robust tactile MAEs in the various tactile motions such as the short-distance motion within the fingertip, the long-distance motion from the finger base to the fingertip, and the circular motion on the fingertip. Our development of a protocol that reliably produces tactile MAEs will provide a useful psychophysical probe into the neural mechanisms of tactile motion processing.
触觉运动感知是实现对触觉世界精细感知的最重要功能之一。为了探索大脑中运动处理的神经动力学，运动适应现象可以作为一个有用的探针。然而，触觉运动后效（MAE）尚未以可重复的方式被报道，先前研究结果不明确可归因于适应和测试刺激的非最佳选择。考虑到研究中使用的刺激的特征，这些刺激在适应和测试阶段激活了不同的机械感受器。因此，我们使用适当的适应和测试刺激组合来测试触觉MAE。我们用三根针在指腹上产生明显运动的感觉。在适应和测试阶段，它们都以30Hz的频率依次振动。预计这个过程确保了在适应和测试阶段对相同机械感受器（快速适应机械感受器）的刺激。使用这个过程，我们在各种触觉运动中发现了强烈的触觉MAE，如指尖内的短距离运动、从手指基部到指尖的长距离运动以及指尖上的圆周运动。我们开发的一种可靠产生触觉MAE的方案将为触觉运动处理的神经机制提供一个有用的心理物理学探针。
