Function of lateral Inhibition in layer 2/3 of adult mouse barrel cortex

新皮层2/3层是躯体感觉系统中第一个神经元站，它以综合的方式处理传入的感觉信息。在桶状皮层中，这些层代表了整合邻近触须触觉信息的第一个站点。因此，第2/3层在感觉刺激的辨别中起着重要作用。这种识别的时空精度主要由层内侧抑制介导，其中具有快速尖峰放电模式的小蛋白免疫反应性（PV+） gaba能中间神经元起核心作用。利用电生理、行为学和光遗传学等方法对成年小鼠的振动系统进行研究，阐明2/3层侧抑制的功能。两个新的行为测试将允许实验分析机械刺激传递到头部固定，操作性条件动物的两个相邻触须之间的空间和时空辨别能力。与此辨别任务相关的神经元活动将用80通道多电极阵列记录在相应的皮质柱上。在B6.Cg-Pvalbtm1.1(cre)Aibs/J转基因小鼠中，通过病毒转染（rAAV2/Flex-Arch-GFP），选择性表达FS-PV+中间神经元中的氯泵archaerhodopin -3 (Arch)，将允许对2/3层侧抑制进行特定和局部的光遗传学操作，并分析由此产生的行为和电生理改变。在体外桶状皮质丘脑皮层切片制备中，我们将在细胞和局部网络水平上研究光遗传学抑制FS-PV+中间神经元的后果。这些体内和体外实验将对生理相关任务中侧抑制的时空特性产生新的见解。

Neocortical layer 2/3 represents the first neuronal station in the somatosensory system which processes incoming sensory information in an integrative manner. In the barrel cortex, these layers represent the first station integrating tactile information from neighbouring whiskers. Therefore, layer 2/3 fulfils an important role in the discrimination of sensory stimuli. The spatio-temporal precision of this discrimination is mostly mediated by intralaminar lateral inhibition, in which parvalbumin-immunoreactive (PV+) GABAergic interneurons with fast spiking (FS) discharge patterns play a central role. Electrophysiological, behavioural and optogenetic methods will be used in the vibrissal system of adult mice to elucidate the function of lateral inhibition in layer 2/3. Two novel behavioural tests will allow the experimental analysis of the spatial and spatio-temporal discrimination capability between mechanical stimuli delivered to two neighbouring vibrissae in head-fixed, operantly conditioned animals. The neuronal activity associated with this discrimination task will be recorded in the corresponding cortical columns with an 80-channel multi-electrode-array. The selective expression of the chloride pump Archaerhodopsin-3 (Arch) in FS-PV+ interneurons via viral transfection (rAAV2/Flex-Arch-GFP) in transgenic mice of the line B6.Cg-Pvalbtm1.1(cre)Aibs/J will allow a specific and local optogenetic manipulation of lateral inhibition in layer 2/3 and the analysis of the resulting behavioural and electrophysiological modifications. The consequence of optogenetic inhibition of FS-PV+ interneurons at the cellular and local network level will be studied in in vitro thalamocortical slice preparations of the barrel cortex. These in vivo and in vitro experiments will yield novel insights to the spatio-temporal properties of lateral inhibition in physiologically relevant tasks.