Contextual modulation in the mammalian primary visual cortex: linking neural circuits to perception

人们普遍认识到，大脑具有处理输入信息的非凡能力。我研究的总体目标是了解大脑中发生的过程，这些过程让我们能够看到周围的世界。尽管眼睛能探测到光，但大多数通常被认为是视觉的东西实际上是由一系列相互关联的大脑区域进行的分析，这些区域被称为膝状体-纹状体通路。*我实验室的研究重点是这条通路的第一个皮质阶段，称为初级视觉皮质(V1)，在这个阶段，单个脑细胞(或神经元)有能力检测视觉场景中的基本特征，例如空间中特定位置的特定方向的线条。单个V1神经元的选择性可以根据之前看到的情况、场景的空间布局，甚至动物当时正在做的事情而改变。由于日常生活中的视觉有时间、空间和行为的背景，研究这种“背景调节”将使我们更完整地理解V1是如何工作的。*长期以来，人们一直猜测，V1神经元的基本特性和背景调节都是通过不同类型神经元之间的特定连接而产生的，这些神经元被称为神经回路。将神经电路与感知联系起来的努力得到了光遗传学领域最近开发的工具的帮助，这些工具使通过照射电路中特定类型的神经元来刺激或抑制它们成为可能。光遗传学工具主要应用于小鼠，我对这个物种有丰富的工作经验。*在我新颖而令人兴奋的研究计划中，我的实验室成员将首次使用小鼠的光遗传学来研究语境调节的几个方面。我们的第一个目标是研究失活的V1或与之相连的大脑区域如何影响语境编码。我们的第二个目标是分离特定类型的V1神经元在语境调制中的作用。我们的第三个目标是建立研究清醒小鼠视觉知觉的技术，以弥合神经回路和知觉之间的差距。*这项拟议的工作将使视觉神经科学界受益，因为它提供了更全面的理解，即V1神经元的特性是如何从神经回路中排列的特定细胞类型产生的。这将有助于改进现有的大脑如何编码视觉信息的模型，并可能为信息如何在整个神经系统中更普遍地呈现提供洞察。更好地理解大脑是如何编码视觉信息的，也可以启发计算机视觉和人工智能的仿生算法。尽管目前这是一个遥远的目标，但开发一种能够像人类(甚至老鼠)一样利用视觉信息与周围环境互动的视觉机器将具有广泛的应用，从安全、制造到太空探索。**

It is widely appreciated that the brain has a remarkable capacity to process incoming information. The overall goal of my research is to understand the processes happening in the brain that allow us to see the world around us. Although the eyes detect light, most of what is commonly thought of as vision actually arises from analyses performed by a chain of interconnected brain regions called the geniculo-striate pathway. *** Research in my laboratory focuses on the first cortical stage of this pathway called the primary visual cortex (V1) where individual brain cells (or neurons) have the ability to detect basic features in a visual scene such as lines of a specific orientation at a particular location in space. The selectivity of an individual V1 neuron can change based on what has been seen previously, the spatial layout of the scene, or even what the animal is doing at the time. Studying this 'contextual modulation' will give a more complete understanding of how V1 works because vision in everyday life has a temporal, spatial, and behavioral context.*** It has long been conjectured that both the basic properties of V1 neurons and contextual modulation arise through specific connections between different types of neurons called neural circuits. Efforts to link neural circuits with perception have been aided by recently developed tools in the field of optogenetics that make it possible to stimulate or suppress specified types of neurons in a circuit by shining light on them. Optogenetic tools are mainly applied in mice, and I have extensive experience working with this species.*** In my novel and exciting research program, members of my lab will use optogenetics in mice to study several aspects of contextual modulation for the first time. Our first objective is to study how inactivating V1 or brain areas that connect with it affects context coding. Our second objective is to isolate the roles of specified types of V1 neurons in contextual modulation. Our third objective is to establish techniques to study visual perception in awake mice to bridge the gap between neural circuits and perception. *** The proposed work will benefit the visual neuroscience community by providing a more comprehensive understanding of how the properties of V1 neurons arise from specific cell types arranged in neural circuits. This will help improve existing models of how the brain codes visual information, and may provide insights into how information is represented more generally across the nervous system. A better understanding of how the brain encodes visual information could also inspire biomimetic algorithms for computer vision and artificial intelligence. Although it is a distant goal at present, the development of a seeing machine with the ability to use visual information to interact with its surroundings just as well as humans (or even mice) would have far reaching applications ranging from security, to manufacturing, to space exploration.**