The function of different classes of inhibitory neurons in the auditory cortex - direct shaping of receptive fields or short-term modulation of the functional circuitry?

听觉皮层构成了我们大脑处理声音的几个阶段的终点。它允许我们对复杂的声音进行分类和识别，例如熟悉的人的声音。另一方面，它在控制对特定听觉对象的注意力方面起着决定性的作用，例如当我们试图在嘈杂的环境中挑选出特定信号时。然而，这些功能背后的机制在很大程度上仍然未知。皮质中的抑制性神经元可能发挥主要作用，并且它们也引起了极大的兴趣，因为它们的功能障碍与几种病理学有关。皮质回路的抑制性元件的理解进展在很大程度上被以下事实所掩盖，即它们分为几个不同的类别，这些类别在体内难以识别。我建议使用新的光遗传学技术来研究小鼠听觉皮层中不同类别的抑制性神经元。在这些技术的帮助下，可以将光敏通道遗传地引入到定义明确的抑制性神经元类别中。因此，这些可以通过照射大脑的光线来选择性地定位和操纵。我的目标是测试关于抑制细胞功能的不同假设：首先，有证据表明这些细胞对皮层的时间精确性和调谐准确性很重要，从而增强了对复杂声音的分类和识别。其次，最近的一个假说声称，抑制控制皮层兴奋细胞之间的功能连接的短期可塑性。这种机制可以通过快速分配更多的计算资源到听觉环境的重要方面来支持选择性注意。识别负责这些功能的细胞类型将大大有助于我们对皮层电路的理解。

The auditory cortex constitutes an end point of several stages of our brain that process sound. It allows us to classify and recognize complex sounds, such as the voice of a familiar person. On the other hand, it plays a decisive role in gating the attention to specific auditory objects, for example when we try to pick out a particular signal against a noisy environment.However, the mechanisms behind these functions remain largely unknown. Inhibitory neurons in the cortex are likely to play a major role, and they are also of great interest because their dysfunction is associated with several pathologies. Progress in the understanding of inhibitory elements of the cortical circuitry has been largely obscured by the fact that they fall into several distinct classes, which are difficult to identify in vivo. I propose to examine different classes of inhibitory neurons in the auditory cortex of mice using new optogenetic techniques. With the help of these techniques, light sensitive channels can be introduced genetically into well defined classes of inhibitory neurons. As a result these can be targeted and manipulated selectively by shining light on the brain. My goal is to test different hypotheses on the function of inhibitory cells: first, there is evidence for these cells to be important for temporal precision and tuning accuracy in the cortex, thereby enhancing the classification and recognition of complex sounds. Second, a recent hypothesis claims that inhibition controls short-term plasticity of the functional connectivity between excitatory cells in the cortex. Such a mechanism could support selective attention by quickly allocating more computational resources to important aspects of the auditory environment. The identification of the cell types that are responsible for these functions would contribute significantly to our understanding of the cortical circuitry.