Hallin R G, Carlstedt T, Wu G
Department of Medical Laboratory Sciences and Technology, Division of Clinical Neurophysiology, Karolinska Institutet, Huddinge University Hospital, 14186 Stockholm, Sweden.
Behav Brain Res. 2002 Sep 20;135(1-2):19-26. doi: 10.1016/s0166-4328(02)00150-x.
Groups of fibres rather than single afferents may be responsible for encoding various intensity aspects of tactile skin stimulation. Reconstruction of population responses of primary afferent fibres to skin displacement provided data in support of this idea, but evidence from direct recordings that demonstrated multifibre activity deriving from groups of single units firing in response to defined skin stimuli were not reported. Procedures are summarised which allow identification and sampling of such recordings in man. For SAII units it was demonstrated how different directions of skin stretch engaging a particular cutaneous area produced different responses of a unit population innervating that site. In response to localised vibratory stimuli synchronous discharges of several co-activated PC afferents were recorded at each vibratory cycle, which is a previously not described pattern of peripheral PC encoding. Population projection of activity within modality segregated clusters of afferents supplying the same skin area might serve as basic projection units and constitute the peripheral counterparts to sensory columns, believed to be the central cognitive correlates, in the cortex. Thus, it is tempting to postulate fibre population projection as a peripheral basis for somatosensory processing in man.
负责编码触觉皮肤刺激各种强度方面的可能是纤维群而非单个传入神经。初级传入纤维对皮肤位移的群体反应重建提供了支持这一观点的数据，但尚未有直接记录的证据表明，在响应特定皮肤刺激时，单个单元群体会产生多纤维活动。本文总结了在人体中识别和采样此类记录的程序。对于II类慢适应单位，研究表明，特定皮肤区域的不同皮肤拉伸方向如何使支配该部位的单位群体产生不同反应。在响应局部振动刺激时，在每个振动周期记录到几个共同激活的后柱核传入神经的同步放电，这是一种以前未描述过的外周后柱核编码模式。在提供相同皮肤区域的传入神经模态分离簇内的活动群体投射可能作为基本投射单元，并构成与感觉柱相对应的外周部分，而感觉柱被认为是皮层中的中枢认知相关物。因此，很容易假设纤维群体投射是人类体感处理的外周基础。
