Deneux Thomas, Masquelier Timothée, Bermudez Maria A, Masson Guillaume S, Deco Gustavo, Vanzetta Ivo
Institut de Neurosciences de la Timone, UMR 7289, CNRS and Aix-Marseille Université, Marseille, France.
Unit of Neuroscience Information and Complexity, CNRS, Gif-sur-Yvette, France.
Neurophotonics. 2017 Jul;4(3):031222. doi: 10.1117/1.NPh.4.3.031222. Epub 2017 Jun 28.
Increasing evidence suggests that sensory stimulation not only changes the level of cortical activity with respect to baseline but also its structure. Despite having been reported in a multitude of conditions and preparations (for instance, as a quenching of intertrial variability, Churchland et al., 2010), such changes remain relatively poorly characterized. Here, we used optical imaging of voltage-sensitive dyes to explore, in V4 of an awake macaque, the spatiotemporal characteristics of both visually evoked and spontaneously ongoing neuronal activity and their difference. With respect to the spontaneous case, we detected a reduction in large-scale activity ([Formula: see text]) in the alpha range (5 to 12.5 Hz) during sensory inflow accompanied by a decrease in pairwise correlations. Moreover, the spatial patterns of correlation obtained during the different visual stimuli were on the average more similar one to another than they were to that obtained in the absence of stimulation. Finally, these observed changes in activity dynamics approached saturation already at very low stimulus contrasts, unlike the progressive, near-linear increase of the mean raw evoked responses over a wide range of contrast values, which could indicate a specific switching in the presence of a sensory inflow.
越来越多的证据表明，感觉刺激不仅会改变皮层活动相对于基线的水平，还会改变其结构。尽管在多种条件和实验准备中都有报道（例如，作为试验间变异性的减弱，Churchland等人，2010年），但这种变化的特征仍然相对不明确。在这里，我们使用电压敏感染料的光学成像技术，在清醒猕猴的V4区探索视觉诱发和自发进行的神经元活动的时空特征及其差异。关于自发情况，我们检测到在感觉输入期间，α波段（5至12.5赫兹）的大规模活动（[公式：见正文]）减少，同时成对相关性降低。此外，在不同视觉刺激期间获得的相关空间模式平均而言彼此之间比在无刺激时获得的模式更相似。最后，与在广泛的对比度值范围内平均原始诱发反应的渐进、近线性增加不同，这些观察到的活动动态变化在非常低的刺激对比度下就已接近饱和，这可能表明在感觉输入存在时发生了特定的转换。
