Awiszus F, Feistner H, Schäfer S S
Abteilung Neurophysiologie (OE 4230), Medizinische Hochschule Hannover, Federal Republic of Germany.
Exp Brain Res. 1991;86(2):440-6. doi: 10.1007/BF00228970.
The peri-stimulus-time histogram (PSTH) analysis of stimulus-related neuronal spike train data is usually regarded as a method to detect stimulus-induced excitations or inhibitions. However, for a fairly regularly discharging neuron such as the human alpha-motoneuron, long-latency modulations of a PSTH are difficult to interpret as PSTH modulations can also occur as a consequence of a modulated neuronal autocorrelation. The experiments reported here were made (i) to investigate the extent to which a PSTH of a human hand-muscle motoneuron may be contaminated by features of the autocorrelation and (ii) to develop methods that display the motoneuronal excitations and inhibitions without such contamination. Responses of 29 single motor units to electrical ulnar nerve stimulation below motor threshold were investigated in the first dorsal interosseous muscle of three healthy volunteers using an experimental protocol capable of demonstrating the presence of autocorrelative modulations in the neuronal response. It was found for all units that the PSTH as well as the cumulative sum (CUSUM) derived from these responses were severely affected by the presence of autocorrelative features. On the other hand, calculating the CUSUM in a slightly modified form yielded--for all units investigated--a neuronal output feature sensitive only to motoneuronal excitations and inhibitions induced by the afferent volley. The price that has to be paid to arrive at such a modified CUSUM (mCUSUM) was a high computational effort prohibiting the on-line availability of this output feature during the experiment. It was found, however, that an interspike interval superposition plot (IISP)--easily obtainable during the experiment--is also free of autocorrelative features.(ABSTRACT TRUNCATED AT 250 WORDS)
刺激相关神经元放电序列数据的刺激时间直方图（PSTH）分析通常被视为检测刺激诱发的兴奋或抑制的一种方法。然而，对于像人类α运动神经元这样放电相当规律的神经元，PSTH的长潜伏期调制很难解释，因为PSTH调制也可能是神经元自相关调制的结果。本文报道的实验旨在：（i）研究人类手部肌肉运动神经元的PSTH受自相关特征影响的程度；（ii）开发能够显示运动神经元兴奋和抑制且不受此类影响的方法。在三名健康志愿者的第一背侧骨间肌中，使用一种能够证明神经元反应中存在自相关调制的实验方案，研究了29个单运动单位对低于运动阈值的尺神经电刺激的反应。结果发现，对于所有单位而言，这些反应得出的PSTH以及累积和（CUSUM）都受到自相关特征的严重影响。另一方面，以略有修改的形式计算CUSUM，对于所有研究的单位，得到了一种仅对传入冲动诱发的运动神经元兴奋和抑制敏感的神经元输出特征。得出这种修改后的CUSUM（mCUSUM）所需付出的代价是计算量很大，这使得该输出特征在实验过程中无法在线获取。然而，发现峰峰间期叠加图（IISP）——在实验过程中很容易获得——也没有自相关特征。（摘要截短于250字）
