Receptive field properties of GABAergic neurons in mouse visual cortex

描述(由申请人提供)：为了了解皮质功能，必须确定包含在感觉输入中的信息是如何在形态和神经化学上不同的单个皮质神经元中表示和处理的。为了了解单个皮质神经元的表征和加工特性的潜在机制，一种盲目的在体全细胞膜片记录技术被应用于检测感觉驱动的兴奋性和抑制性突触对皮质神经元的输入。这类研究的结果为研究皮层神经元反应特性的突触回路机制提供了新的见解。虽然这项技术可以与后组织学方法相结合来重建记录细胞的形态，但它的盲性在很大程度上限制了它在检查皮质各种细胞类型方面的潜力，因为它通常会导致对皮层兴奋性锥体神经元的偏向采样。在这个探索性的项目中，我们将研究一种新的技术来揭示在体大脑皮质抑制性神经元的功能特性和突触输入，即双光子成像引导的斑片记录(TPGP)，其中荧光标记的神经元通过双光子成像被可视化，并专门用于斑片记录。这项技术得益于小鼠遗传学的最新发展，即用绿色荧光蛋白(GFP)等荧光蛋白标记特定类型的细胞，其表达受细胞类型特定启动子的控制。在第一步，我们将把这种记录技术应用于GFP标记的小鼠初级视觉皮质(V1)颗粒上层(L1-3)的GABA能中间神经元，以研究这些神经元的感受野特性，以及这些特性是如何由视觉激活的兴奋性和抑制性突触输入的整合决定的。

DESCRIPTION (provided by applicant): To understand cortical functions, it is essential to determine how information contained in sensory input is represented and processed in individual cortical neurons that are morphologically and neurochemically diverse. To understand mechanisms underlying the representational and processing properties of individual cortical neurons, a blind, in vivo, whole-cell patch-recording technique has been applied to examine sensory-driven excitatory and inhibitory synaptic inputs onto cortical neurons. Results from such studies have provided new insights into synaptic circuit mechanism underlying cortical neurons' response properties. Although this technique can be combined with post hoc histological methods to reconstruct the morphology of recorded cells, its blind nature largely limits its potential in examining various cell types in the cortex, since it normally results in a biased sampling of excitatory pyramidal neurons in the cortex. In this exploratory project, we will study a new technique for revealing functional properties and synaptic inputs of inhibitory cortical neurons in vivo, two-photon imaging guided patch recording (TPGP) in which fluorescently labeled neurons are visualized by two-photon imaging and specifically targeted for patch recording. This technique has benefited from recent development of mouse genetics in labeling cells of specific types with fluorescence proteins such as green fluorescence protein (GFP), with their expression controlled by cell-type specific promoters. At an initial step, we will apply this recording technique to GFP-labeled GABAergic interneurons in the supragranular layers (L1-3) of mouse primary visual cortex (V1), to address the receptive field properties of these neurons and how these properties are determined by the integration of visually activated excitatory and inhibitory synaptic inputs.