Somatotopic dominance in tactile temporal processing
Somatotopic dominance in tactile temporal processing
复制标题
DOI：
10.1007/s00221-010-2212-8
复制
发表时间：
2010-05-01
影响因子：
2
通讯作者：
Nishida, Shin'ya
中科院分区：
文献类型：
--
作者：
Kuroki, Shinobu;Watanabe, Junji;Nishida, Shin'ya
触觉是通过刺激外周机械感受器启动的，然后通过中央皮层处理解释感受器激活的时空模式。为了探索触觉中枢处理，我们心理学研究了人类对发生在不同皮肤位置的两个触觉事件之间的时间关系的判断。我们研究了四种类型的两点时间判断的一致性，时间顺序，明显的运动，和刺激间的时间间隔，这是不同的时间尺度和任务要求。为了完成四个时间判断任务中的任何一个，大脑必须整合空间上分离的输入。本研究的主要目的是考察空间分离对时间判断任务的影响。两个空间坐标可以在触摸中定义：躯体位置坐标，由皮质地形定义，和空间位置坐标，在环境中定义。在我们的实验中，通过刺激同一只手或不同手的中指和食指（同侧与双侧条件）来操纵躯体位置距离，而通过在双侧条件下增加刺激器的分离来操纵空间位置距离（双侧-近与双侧-远条件）。我们的研究结果清楚地表明，所有四个时间的判断显着影响的躯体空间距离，但只有轻微的空间距离。目前的结果，连同以前的研究结果，表明，触觉时间的判断在很宽的时间尺度，从几个到几个100毫秒，主要反映在躯体位置的代表性的水平上的处理，除非性能进一步受到空间处理的限制。
The sense of touch is initiated by stimulation of peripheral mechanoreceptors, and then the spatio-temporal pattern of the receptors' activation is interpreted by central cortical processing. To explore the tactile central processing, we psychophysically studied human judgments of the temporal relationships between two tactile events occurring at different skin locations. We examined four types of two-point temporal judgments-simultaneity, temporal order, apparent motion, and inter-stimulus interval-which differ from one another in time scale and task requirement. To perform any of the four temporal judgment tasks, the brain has to integrate spatially separated inputs. The main focus of the present study is to examine how the spatial separation affects the temporal judgment tasks. Two spatial coordinates can be defined in touch: the somatotopic coordinate, defined by cortical topography, and the spatiotopic coordinate, defined in the environment. In our experiments, the somatotopic distance was manipulated by stimulating the middle and index fingers of the same hand or different hands (ipsilateral vs. bilateral conditions), while the spatiotopic distance was manipulated by increasing the stimulators' separation under bilateral conditions (bilateral-near vs. bilateral-far conditions). Our results clearly demonstrated that all four of the temporal judgments were significantly affected by the somatotopic distance, but only slightly by the spatiotopic distance. The present results, together with the previous findings, suggest that tactile temporal judgments in a wide range of time scale, from several to several 100 ms, primarily reflect processing at the level of somatotopic representation unless the performance is further constrained by spatial processing.