Eggermont J J, Smith G M
Department of Psychology, University of Calgary, Alberta, Canada.
Exp Brain Res. 1996 Aug;110(3):379-91. doi: 10.1007/BF00229138.
In order to allow the relation of functional connectivity patterns (inferred from cross-correlograms) to structural connectivity (the anatomical substrate), we analyzed cross-correlogram peaks for spontaneous and stimulated activity in the auditory cortex. It was assumed that the broad correlograms, usually encountered, represent neural connectivity as well as secondary effects such as intrinsic firing patterns, global synchrony related to the ongoing electroencephalographic activity, and stimulus-related effects. Data were collected from 604 neuron pairs recorded under spontaneous conditions in primary auditory cortex of seven juvenile (30-70 days) and nine adult cats. Three hundred and six pairs (51%) had a peak cross-correlation coefficient significantly different from zero. For 113 neuron pairs out of this subgroup, correlations were calculated also for spike trains recorded during click stimulation. After a combined burst-correction and deconvolution procedure was carried out, the correlation peak strengths were not significantly changed for spontaneous activity, but peak width was narrower for single-electrode pairs than for dual-electrode pairs, suggesting a better synchronization for neighboring neurons. Under click stimulation conditions, overall peak synchronization strength was independent of interelectrode distance, whereas, after correction for secondary and stimulus effects, peak synchronization was significantly lower for dual-electrode pairs. However, the primary peak width for single-electrode pairs under stimulus conditions was no longer different from that of dual-electrode pairs. This implies that both under spontaneous and stimulus conditions secondary effects largely obscure any underlying correlation produced by anatomical connectivity. The secondary effects may be the result of intrinsic as well as network properties in auditory cortex and may functionally be more important than the weak primary effects resulting from anatomical connections. Cross-interval analysis suggests that the correlations in auditory cortex are dynamic and may show random switching between states of stronger and weaker synchronization.
为了探究功能连接模式（从互相关图推断得出）与结构连接（解剖学基础）之间的关系，我们分析了听觉皮层中自发活动和刺激活动的互相关图峰值。我们假设，通常遇到的宽泛互相关图既代表神经连接，也代表诸如内在放电模式、与持续脑电图活动相关的全局同步以及刺激相关效应等次要效应。数据收集自7只幼年（30 - 70天）和9只成年猫初级听觉皮层在自发条件下记录的604对神经元。其中306对（51%）的互相关系数峰值显著不同于零。在这个子组中的113对神经元，我们还计算了在点击刺激期间记录的脉冲序列的相关性。在进行了联合脉冲校正和去卷积程序后，自发活动的相关性峰值强度没有显著变化，但单电极对的峰值宽度比双电极对更窄，这表明相邻神经元的同步性更好。在点击刺激条件下，总体峰值同步强度与电极间距离无关，然而，在校正次要效应和刺激效应后，双电极对的峰值同步性显著更低。但是，刺激条件下单电极对的主要峰值宽度与双电极对不再有差异。这意味着在自发和刺激条件下，次要效应在很大程度上掩盖了由解剖连接产生的任何潜在相关性。次要效应可能是听觉皮层内在特性以及网络特性的结果，并且在功能上可能比解剖连接产生的微弱主要效应更重要。交叉间隔分析表明，听觉皮层中的相关性是动态的，可能在较强和较弱同步状态之间随机切换。
