Circuit mechanisms underlying cortical communications

为了了解大脑皮层通信中远程连接的原理，我们在2020财年期间重点开展了以下两个项目。 不同的远程输入到感觉皮质的功能连接旨在实现对反馈/自上而下的投射到初级感觉皮质的功能连接的机械性理解。我们系统地研究了初级体感皮质(S1)不同脑区到不同神经元类型的突触强度，并确定了初级感觉皮质如何利用输入区域依赖的、优先招募的特定类型的GABA能中间神经元来解析来自不同反馈投影的信息。目前正在审查这项研究的结果。 第二个项目，大脑皮层网络的结构组织，旨在了解支配感觉皮层主神经元功能异质性的原理。初级感觉皮层浅层的神经元活动与动物行为的各个方面具有高度的异质性。我们询问了功能上的异构子网络是否受到特定的远程和局部突触前集合的限制。这项研究为大脑皮层网络的组织提供了基于电路的机制。利用单细胞启动、单突触狂犬病病毒示踪结合钙离子成像，我们发现行为状态编码(自发运动)神经元显示出特有的远距离和局部突触前网络。我们的结果揭示了支持大脑皮层主细胞功能异质性的连通性规则。我们目前正在准备一份关于这项研究的手稿。

In order to understand the principles of long-range connectivity in cortical communication, our efforts have focused on the following two projects during FY20. Functional connectivity of diverse long-range inputs to sensory cortex is aimed at achieving a mechanistic understanding of the functional connectivity of feedback / top-down projections to the primary sensory cortex. We have systematically examined the synaptic strength from different brain areas to diverse neuronal types in the primary somatosensory cortex (S1) and determined how the primary sensory cortex uses input-area-dependent, preferential recruitment of specific types of GABAergic interneurons to parse information from diverse feedback projections. The results of this study are currently under review. The second project, The structural organization of cortical subnetworks, is aimed at understanding the principles that govern the functional heterogeneity of principal neurons in sensory cortex. Neuronal activity in the superficial layer of the primary sensory cortex is highly heterogenous in relation to various aspects of the animals behavior. We asked whether functionally heterogeneous subnetworks are constrained by specific long-range and local presynaptic ensembles. This study provides the circuit-based mechanism for the organization of cortical subnetworks. Using single cell-initiated, monosynaptic rabies virus tracing combined with calcium imaging, we found that behavior state-encoding (spontaneous movement) neurons show characteristic long-range and local presynaptic networks. Our results reveal connectivity rules that support functional heterogeneity of cortical principal cells. We are currently preparing a manuscript on this study.