Electrical and Computer Engineering Department, Carnegie Mellon University, Pittsburgh, PA, USA.
Dominick Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY, USA.
Nat Commun. 2022 Mar 1;13(1):1099. doi: 10.1038/s41467-022-28552-w.
Brain function relies on the coordination of activity across multiple, recurrently connected brain areas. For instance, sensory information encoded in early sensory areas is relayed to, and further processed by, higher cortical areas and then fed back. However, the way in which feedforward and feedback signaling interact with one another is incompletely understood. Here we investigate this question by leveraging simultaneous neuronal population recordings in early and midlevel visual areas (V1-V2 and V1-V4). Using a dimensionality reduction approach, we find that population interactions are feedforward-dominated shortly after stimulus onset and feedback-dominated during spontaneous activity. The population activity patterns most correlated across areas were distinct during feedforward- and feedback-dominated periods. These results suggest that feedforward and feedback signaling rely on separate "channels", which allows feedback signals to not directly affect activity that is fed forward.
大脑功能依赖于多个反复连接的脑区之间活动的协调。例如，早期感觉区编码的感觉信息被传递到更高的皮质区，并进一步处理，然后反馈。然而，前馈和反馈信号相互作用的方式尚未完全了解。在这里，我们通过利用早期和中级视觉区（V1-V2 和 V1-V4）中的同时神经元群体记录来研究这个问题。使用降维方法，我们发现群体相互作用在刺激开始后不久主要是前馈主导，在自发活动期间主要是反馈主导。在前馈和反馈主导期间，跨区最相关的群体活动模式是不同的。这些结果表明，前馈和反馈信号依赖于单独的“通道”，这使得反馈信号不会直接影响前馈的活动。
