Desmedt J E
Unité de Recherche sur le Cerveau, Faculté de Médecine, Université de Bruxelles, Belgique.
J Physiol (Paris). 1987;82(2):64-136.
The physiology of somatic sensation can be investigated noninvasively in man by recording the electric activity of peripheral nerves, spinal cord and brain. Since these responses have a small voltage, it is necessary to use electronic averaging methods for improving the signal-to-noise ratio. These methods are described and discussed, as well as principles of interpretation of somatosensory evoked potentials. It is agreed that the traces thus obtained involve a series of components (extracellular potentials) which reflect distinct neural generators. These generators have been identified and localized at different levels of the subcortical somatosensory pathway and in different cortical areas. Several components reflect generators located under the recording electrodes (nearfield potentials), while other reflect extracellular potentials diffusing at a distance in the volume conductor of the neck and head (farfield potentials). The analysis of these components provides a wealth of new data for the physiology and pathophysiology of the somatic sensory system in man. Besides so-called "obligatory" components that are present irrespective of the attention of the subject, the studies have uncovered "cognitive" components which reflect neural mechanisms involved in the intellectual processus of perception and decision.
通过记录外周神经、脊髓和大脑的电活动，可以在人体上以非侵入性方式研究躯体感觉的生理学。由于这些反应的电压很小，因此有必要使用电子平均方法来提高信噪比。本文描述并讨论了这些方法以及体感诱发电位的解释原则。大家一致认为，由此获得的痕迹涉及一系列反映不同神经发生器的成分（细胞外电位）。这些发生器已在皮质下躯体感觉通路的不同水平和不同皮质区域被识别和定位。几个成分反映位于记录电极下方的发生器（近场电位），而其他成分反映在颈部和头部的容积导体中远距离扩散的细胞外电位（远场电位）。对这些成分的分析为人体躯体感觉系统的生理学和病理生理学提供了大量新数据。除了无论受试者是否注意都会出现的所谓“强制性”成分外，这些研究还发现了“认知”成分，这些成分反映了参与感知和决策智力过程的神经机制。
