Harrington Program, Biomedical Engineering, Arizona State University, Tempe, AZ 85287, USA.
IEEE Trans Neural Syst Rehabil Eng. 2011 Oct;19(5):490-500. doi: 10.1109/TNSRE.2011.2166808.
Somatosensation is divided into multiple discrete modalities that we think of separably: e.g., tactile, proprioceptive, and temperature sensation. However, in processes such as haptics,those modalities all interact. If one intended to artificially generate a sensation that could be used for stereognosis, for example, it would be crucial to understand these interactions. We are presently examining the relationship between tactile and proprioceptive modalities in this context. In this overview of some of our recent work, we show that signals that would normally be attributed to two of these systems separately, tactile contact and self-movement, interact both perceptually and physiologically in ways that complicate the understanding of haptic processing. In the first study described here, we show that a tactile illusion on the fingertips, the cutaneous rabbit effect, can be abolished by changing the posture of the fingers. We then discuss activity in primary somatosensory cortical neurons illustrating the interrelationship of tactile and postural signals. In this study, we used a robot-enhanced virtual environment to show that many neurons in primary somatosensory cortex with cutaneous receptive fields encode elements both of tactile contact and self-motion. We then show the results of studies examining the structure of the process which extracts the spatial location of the hand from proprioceptive signals. The structure of the spatial errors in these maps indicates that the proprioceptive-spatial map is stable but individually constructed.These seemingly disparate studies lead us to suggest that tactile sensation is encoded in a 2-D map, but one which undergoes continual dynamic modification by an underlying proprioceptive map. Understanding how the disparate signals that comprise the somatosensory system are processed to produce sensation is an important step in realizing the kind of seamless integration aspired to in neuroprosthetics.
躯体感觉分为多种离散的模式，我们可以将它们分开考虑：例如触觉、本体感觉和温度感觉。然而，在触觉等过程中，这些模式会相互作用。例如，如果要人为产生一种可用于触觉辨认的感觉，就必须了解这些相互作用。在这方面，我们目前正在研究触觉和本体感觉模式之间的关系。在本文对我们近期部分工作的概述中，我们表明，通常归因于这两个系统之一的信号——触觉接触和自身运动，在感知和生理上以复杂的方式相互作用，这使得对触觉处理的理解变得复杂。在本文描述的第一项研究中，我们表明，指尖的触觉错觉——皮肤兔子效应，可以通过改变手指的姿势来消除。然后，我们讨论了初级躯体感觉皮层神经元的活动，说明了触觉和姿势信号的相互关系。在这项研究中，我们使用机器人增强的虚拟环境表明，初级躯体感觉皮层中具有皮肤感受野的许多神经元编码触觉接触和自身运动的元素。然后，我们展示了研究从本体感觉信号中提取手部空间位置的过程结构的结果。这些地图中空间误差的结构表明，本体感觉-空间地图是稳定的，但由个体构建。这些看似不同的研究使我们得出结论，即触觉是在二维地图中编码的，但它会受到底层本体感觉地图的持续动态修改。了解构成躯体感觉系统的不同信号如何被处理以产生感觉，是实现神经假肢所期望的那种无缝集成的重要步骤。
