Laboratory of Neural Circuit Dynamics, Brain Research Institute, University of Zurich, Switzerland.
Laboratory of Neural Circuit Dynamics, Brain Research Institute, University of Zurich, Switzerland.
Neuroscience. 2018 Jan 1;368:57-69. doi: 10.1016/j.neuroscience.2017.09.003. Epub 2017 Sep 14.
A fundamental task frequently encountered by brains is to rapidly and reliably discriminate between sensory stimuli of the same modality, be it distinct auditory sounds, odors, visual patterns, or tactile textures. A key mammalian brain structure involved in discrimination behavior is the neocortex. Sensory processing not only involves the respective primary sensory area, which is crucial for perceptual detection, but additionally relies on cortico-cortical communication among several regions including higher-order sensory areas as well as frontal cortical areas. It remains elusive how these regions exchange information to process neural representations of distinct stimuli to bring about a decision and initiate appropriate behavioral responses. Likewise, it is poorly understood how these neural computations are conjured during task learning. In this review, we discuss recent studies investigating cortical dynamics during discrimination behaviors that utilize head-fixed behavioral tasks in combination with in vivo electrophysiology, two-photon calcium imaging, and cell-type-specific targeting. We particularly focus on information flow in distinct cortico-cortical pathways when mice use their whiskers to discriminate between different objects or different locations. Within the primary and secondary somatosensory cortices (S1 and S2, respectively) as well as vibrissae motor cortex (M1), intermingled functional representations of touch, whisking, and licking were found, which partially re-organized during discrimination learning. These findings provide first glimpses of cortico-cortical communication but emphasize that for understanding the complete process of discrimination it will be crucial to elucidate the details of how neural processing is coordinated across brain-wide neuronal networks including the S1-S2-M1 triangle and cortical areas beyond.
大脑经常面临的一项基本任务是快速而可靠地辨别同一感觉模式的刺激，无论是不同的听觉声音、气味、视觉模式还是触觉纹理。参与辨别行为的哺乳动物大脑的关键结构是新皮层。感觉处理不仅涉及对感知检测至关重要的各自初级感觉区，还依赖于包括高级感觉区和额皮质区在内的几个区域之间的皮质-皮质通讯。这些区域如何交换信息来处理不同刺激的神经表示以做出决策并引发适当的行为反应，仍然难以捉摸。同样，在任务学习过程中如何产生这些神经计算也知之甚少。在这篇综述中，我们讨论了最近的研究，这些研究调查了利用头部固定行为任务结合体内电生理学、双光子钙成像和细胞类型特异性靶向技术研究辨别行为中的皮质动力学。我们特别关注当老鼠用胡须辨别不同物体或不同位置时，不同皮质-皮质通路中的信息流。在初级和次级体感皮层（S1 和 S2）以及触须运动皮层（M1）中，发现了触摸、触须运动和舔舐的功能混合表示，这些表示在辨别学习过程中部分重新组织。这些发现提供了皮质间通讯的初步见解，但强调为了理解辨别过程的全貌，阐明神经处理如何在包括 S1-S2-M1 三角区和皮层以外的广泛脑神经网络中的协调细节将至关重要。
