French Andrew S, Dick Susan H, Rasmusson Douglas D
Department of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia B3H 4H7, Canada.
J Neurophysiol. 2002 Dec;88(6):3372-6. doi: 10.1152/jn.00329.2002.
In a previous study, we reported evidence for correlations between the firing of postsynaptic dorsal column (PSDC) neurons and cuneate neurons with overlapping receptive fields on the glabrous skin of the raccoon forepaw. The evidence was based on cross-correlation and frequency response analyses of spontaneously firing neurons. However, cross-correlation without white noise Gaussian analog inputs or Poisson distributed pulse train inputs is difficult to interpret because of the inherent convolution with the autocorrelation of the unknown input signals. While the data suggested positive correlations in the spinocuneate direction for most neuron pairs, we could not estimate the temporal characteristics of these putative connections. We have now re-analyzed these data using a parallel-cascade method to estimate the first- and second-order kernels of a Volterra series approximation to the spinocuneate system. This unbiased analysis suggests that a positive correlation occurs after about 5 ms, probably followed by a negative correlation at about 12 ms. Second-order kernels also had repeatable structure, indicating dual pathways with time separations of at least 10 ms.
在之前的一项研究中，我们报告了有关突触后背柱（PSDC）神经元和楔束神经元放电之间相关性的证据，这些神经元在浣熊前爪无毛皮肤上具有重叠的感受野。该证据基于对自发放电神经元的互相关和频率响应分析。然而，由于与未知输入信号的自相关存在固有卷积，没有白噪声高斯模拟输入或泊松分布脉冲序列输入的互相关很难解释。虽然数据表明大多数神经元对在脊髓楔束方向上存在正相关，但我们无法估计这些假定连接的时间特征。我们现在使用并行级联方法重新分析了这些数据，以估计脊髓楔束系统的沃尔泰拉级数近似的一阶和二阶核。这种无偏分析表明，大约在5毫秒后出现正相关，随后可能在大约12毫秒时出现负相关。二阶核也具有可重复的结构，表明存在时间间隔至少为10毫秒的双重通路。
