Public University of Navarra, Department of Electrical and Electronic Engineering, 31006 Pamplona, Spain.
J Electromyogr Kinesiol. 2013 Feb;23(1):24-32. doi: 10.1016/j.jelekin.2012.07.003. Epub 2012 Aug 4.
Studies dealing with single fibre action potentials (SFAPs) have been more interested in obtaining quantitative data of certain parameters of the SFAP waveform than in the analysis of its morphologic features. The characterization of the SFAP morphology is highly valuable as it will allow to obtain information about in vivo intracellular action potentials (IAPs). However, the SFAP final portion is highly sensitive to distant electrical activity, as shown in Part I of this study. The present paper, Part II, is aimed at analysing the morphologies found in human SFAPs and deriving data of the associated IAPs. It was found that, for most SFAPs (97%), the declining negative phase starts decreasing steeply up to a certain point (slope-discontinuity point), from which it returns more slowly towards the baseline. This return may be further slowed down due to the contamination from distant potentials, but the slope-discontinuity point seems to be an intrinsic feature of human SFAPs. The third phase of SFAPs was, either absent (65%), or of rather small amplitude and prolonged duration. The slope-discontinuity point was apparent for the SFAPs of larger amplitude and vanished gradually as the SFAPs got smaller. Several lines of evidence strongly suggest that the spike duration of human IAPs should be about 1.0 ms.
研究单纤维动作电位 (SFAP) 的人更感兴趣的是获得 SFAP 波形某些参数的定量数据，而不是分析其形态特征。SFAP 形态的特征非常有价值，因为它将允许获得关于体内细胞内动作电位 (IAP) 的信息。然而，如本研究第一部分所示，SFAP 的最终部分对远距离电活动非常敏感。本文的第二部分旨在分析在人类 SFAPs 中发现的形态，并得出相关 IAP 的数据。结果发现，对于大多数 SFAPs（97%），下降的负相开始急剧下降，直到某个点（斜率不连续点），从该点开始，它以较慢的速度向基线返回。由于受远距离电势的干扰，这种返回可能会进一步减慢，但斜率不连续点似乎是人类 SFAPs 的固有特征。SFAPs 的第三阶段要么不存在（65%），要么幅度较小且持续时间较长。斜率不连续点对于幅度较大的 SFAPs 是明显的，并且随着 SFAPs 变小逐渐消失。有几条证据强烈表明，人类 IAP 的尖峰持续时间应为 1.0 ms。
