Sobolewski Aleksander, Kublik Ewa, Swiejkowski Daniel A, Lęski Szymon, Kamiński Jan K, Wróbel Andrzej
Nencki Institute of Experimental Biology-Polish Academy of Sciences, 3 Pasteur St., 02-093, Warsaw, Poland.
J Comput Neurosci. 2010 Dec;29(3):485-93. doi: 10.1007/s10827-010-0220-0. Epub 2010 Feb 23.
We describe a computational method for assessing functional connectivity in sensory neuronal networks. The method, which we term cross-trial correlation, can be applied to signals representing local field potentials (LFPs) evoked by sensory stimulations and utilizes their trial-to-trial variability. A set of single trial samples of a given post-stimulus latency from consecutive evoked potentials (EPs) recorded at a given site is correlated with such sets for all other latencies and recording sites. The results of this computation reveal how neuronal activities at various sites and latencies correspond to activation of other sites at other latencies. The method was used to investigate the functional connectivity of thalamo-cortical network of somatosensory system in behaving rats at two levels of alertness: habituated and aroused. We analyzed potentials evoked by vibrissal deflections recorded simultaneously from the ventrobasal thalamus and barrel cortex. The cross-trial correlation analysis applied to the early post-stimulus period (<25 ms) showed that the magnitude of the population spike recorded in the thalamus at 5 ms post-stimulus correlated with the cortical activation at 6-13 ms post-stimulus. This correlation value was reduced at 6-9 ms, i.e. at early postsynaptic cortical response, with increased level of the animals' arousal. Similarly, the aroused state diminished positive thalamo-cortical correlation for subsequent early EP waves, whereas the efficacy of an indirect cortico-fugal inhibition (over 15 ms) did not change significantly. Thus we were able to characterize the state related changes of functional connections within the thalamo-cortical network of behaving animals.
我们描述了一种用于评估感觉神经元网络中功能连接性的计算方法。我们将这种方法称为跨试验相关性，它可应用于表示感觉刺激诱发的局部场电位（LFP）的信号，并利用其试验间的变异性。从给定部位记录的连续诱发电位（EP）中，一组给定刺激后潜伏期的单次试验样本与所有其他潜伏期和记录部位的此类样本进行相关性分析。该计算结果揭示了不同部位和潜伏期的神经元活动如何与其他潜伏期其他部位的激活相对应。该方法用于研究行为大鼠在两种警觉水平（习惯化和觉醒）下体感系统丘脑 - 皮质网络的功能连接性。我们分析了同时从腹侧基底丘脑和桶状皮质记录的触须偏转诱发的电位。应用于刺激后早期（<25毫秒）的跨试验相关性分析表明，刺激后5毫秒在丘脑中记录的群体峰电位幅度与刺激后6 - 13毫秒的皮质激活相关。在6 - 9毫秒，即突触后皮质早期反应时，随着动物觉醒水平的提高，这种相关值降低。同样，觉醒状态减弱了随后早期EP波的丘脑 - 皮质正相关性，而间接皮质 - 离心抑制（超过15毫秒）的效果没有显著变化。因此，我们能够表征行为动物丘脑 -皮质网络内功能连接的状态相关变化。
