Hallin R G, 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):11-8. doi: 10.1016/s0166-4328(02)00149-3.
Microneurography with tungsten electrodes has provided a wealth of new data on peripheral nerve fibre function in man. Yet, some lingering controversies pertaining to the technique and its results have not been resolved. In particular, the working principles of microneurography allowing single unit sampling in man are not fully understood. Additionally debated, especially during recent years, was the validity of some neurographic data which supported the long standing conventional concept that myelinated fibres are randomly distributed intraneurally. A novel approach to address these issues was provided by microneurography with concentric needle electrodes. Data obtained with the latter technique suggested that these electrodes record activity extraaxonally from single myelinated fibres in man, possibly at or close to a node of Ranvier. The mechanisms described, which allow single unit resolution in humans, might well also be valid when performing microneurography with tungsten electrodes. Other sets of data indicated that Ranvier nodes tend to occur in clusters within certain regions of a nerve fascicle. Interestingly, the nerve fibres belonging to these clustering nodes were of the same modality and tended to innervate the same skin area in the hand. The discovered nerve fibre segregation involved all the four main classes of myelinated low threshold skin afferents in the hand (RA, PC, SAI and SAII units). The fact that sensory nerve fibres with clustering nodes and of the same modality tend to run together suggests at least a partially ordered intrafascicular nerve fibre organisation. The demonstrated intraneural fibre systematisation could be of profound functional significance both under normal conditions and in disease
使用钨电极的微神经ography为人类周围神经纤维功能提供了大量新数据。然而，一些与该技术及其结果相关的长期争议尚未得到解决。特别是，微神经ography在人类中进行单单位采样的工作原理尚未完全理解。此外，近年来尤其受到争议的是一些神经graphic数据的有效性，这些数据支持了长期以来的传统概念，即有髓纤维在神经内随机分布。使用同心针电极的微神经ography提供了一种解决这些问题的新方法。用后一种技术获得的数据表明，这些电极在人类中从单个有髓纤维的轴突外记录活动，可能在郎飞结处或其附近。所描述的机制允许在人类中进行单单位分辨，在使用钨电极进行微神经ography时可能同样有效。其他数据集表明，郎飞结倾向于在神经束的某些区域内成簇出现。有趣的是，属于这些成簇节点的神经纤维具有相同的模式，并且倾向于支配手部的相同皮肤区域。发现的神经纤维分离涉及手部有髓低阈值皮肤传入的所有四个主要类别（RA、PC、SAI和SAII单位）。具有成簇节点且模式相同的感觉神经纤维倾向于一起运行这一事实表明，神经束内至少存在部分有序的神经纤维组织。所证明的神经内纤维系统化在正常条件下和疾病中可能都具有深远的功能意义。
