Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.
Wiley Interdiscip Rev Syst Biol Med. 2014 May-Jun;6(3):279-87. doi: 10.1002/wsbm.1267. Epub 2014 Mar 19.
Specialized mechanoreceptors in the skin respond to mechanical deformation and provide the primary input to the tactile sensory system. Although the morphology of these receptors has been documented, there is still considerable uncertainty as to the relation between cutaneous receptor morphology and the associated physiological responses to stimulation. Labelled-line models of somatosensory processes in which specific mechanoreceptors are associated with particular sensory qualities fail to account for the evidence showing that all types of tactile afferent units respond to a varying extent to most types of natural stimuli. Neurophysiological and psychophysical experiments have provided the framework for determining the relation between peripheral afferent or cortical activity and tactile perception. Neural codes derived from these afferent signals are evaluated in terms of their capacity to predict human perceptual performance. One particular challenge in developing models of the tactile sensory system is the dual use of sensory signals from the skin. In addition to their perceptual function they serve as inputs to the sensorimotor control system involved in manipulation. Perceptions generated through active touch differ from those resulting from passive stimulation of the skin because they are the product of self-generated exploratory processes. Recent research in this area has highlighted the importance of shear forces in these exploratory movements and has shown that fingertip skin is particularly sensitive to shear generated during both object manipulation and tactile exploration.
皮肤中的专门机械感受器对机械变形做出反应，并为触觉感知系统提供主要输入。尽管这些感受器的形态已经被记录下来，但关于皮肤感受器形态与刺激相关的生理反应之间的关系仍然存在很大的不确定性。体感过程的标记线模型认为，特定的机械感受器与特定的感觉质量有关，但该模型无法解释这样的证据，即所有类型的触觉传入单位在不同程度上对大多数类型的自然刺激都有反应。神经生理学和心理物理学实验为确定外周传入或皮层活动与触觉感知之间的关系提供了框架。从这些传入信号中得出的神经代码根据其预测人类感知性能的能力进行评估。开发触觉感知系统模型的一个特别挑战是皮肤感觉信号的双重用途。除了它们的感知功能外，它们还作为涉及操作的感觉运动控制系统的输入。主动触摸产生的感知与被动刺激皮肤产生的感知不同，因为它们是自我产生的探索过程的产物。该领域的最新研究强调了这些探索性运动中剪切力的重要性，并表明指尖皮肤对物体操作和触觉探索过程中产生的剪切力特别敏感。
