Department of Neurobiology, Weizmann Institute of Science, Rehovot, Israel.
Nat Commun. 2021 Jul 2;12(1):4095. doi: 10.1038/s41467-021-24310-6.
Interhemispheric correlation between homotopic areas is a major hallmark of cortical physiology and is believed to emerge through the corpus callosum. However, how interhemispheric correlations and corpus callosum activity are affected by behavioral states remains unknown. We performed laminar extracellular and intracellular recordings simultaneously from both barrel cortices in awake mice. We find robust interhemispheric correlations of both spiking and synaptic activities that are reduced during whisking compared to quiet wakefulness. Accordingly, optogenetic inactivation of one hemisphere reveals that interhemispheric coupling occurs only during quiet wakefulness, and chemogenetic inactivation of callosal terminals reduces interhemispheric correlation especially during quiet wakefulness. Moreover, in contrast to the generally elevated firing rate observed during whisking epochs, we find a marked decrease in the activity of imaged callosal fibers. Our results indicate that the reduction in interhemispheric coupling and correlations during active behavior reflects the specific reduction in the activity of callosal neurons.
大脑两半球间同源区的相互关联是皮质生理学的主要特征，并且据信是通过胼胝体实现的。然而，行为状态如何影响大脑两半球间的关联和胼胝体的活动尚不清楚。我们在清醒的小鼠中同时进行了层状细胞外和细胞内记录。我们发现，在与安静觉醒相比，刷动期间，无论是放电活动还是突触活动都存在着较强的大脑两半球间相关性，且这种相关性有所减弱。相应地，用光遗传学方法使一侧大脑半球失活表明，大脑两半球间的偶联仅发生在安静觉醒期间，而利用化学遗传学方法使胼胝体末端失活则会特别降低安静觉醒时的大脑两半球间相关性。此外，与刷动期间观察到的普遍升高的放电率相反，我们发现被成像的胼胝体纤维的活动明显下降。我们的研究结果表明，在活跃行为期间大脑两半球间偶联和相关性的减少反映了胼胝体神经元活动的特异性减少。
