Functional connectivity in primary visual cortex

描述（由申请人提供）：视觉皮层功能的准确模型需要精确了解视觉刺激如何在皮层内表示以及参与此表示的特定电路。这一知识不仅对理解大脑中的视觉处理很重要，而且对未来使用皮质假体也很重要，这种假体可以通过电微刺激为盲人提供视觉。在过去的几年里，人们一直在努力研究线方向和视觉空间是如何在初级视觉皮层内映射的，以及这些表征是如何通过不同类型的皮层内连接（水平连接、反馈连接和局部皮层内连接）联系起来的。然而，膝皮质连接的等效测量仍然缺失。我们的知识中的这一差距是非常重要的，因为膝状皮质连接是视觉信息进入大脑的主要入口，它们的功能组织与视觉空间的皮质表征密切相关。由于缺乏这些数据，目前的皮质功能模型使用非常不同的膝状体皮质连接模式，从那些假设传入神经的随机分布到那些假设膝状体感受野沿着每个皮质域的首选方向整齐排列的模型。在这项提案中，我们将使用一个新的，强大的组合多电极记录，光学成像和神经元示踪技术，以填补这一重要的知识空白，并提供新的实验限制模型的皮质功能。我们的实验将揭示组织的膝状皮质通路在亚毫米尺度和这种微组织的作用，在表示线的方向和视觉空间内的皮层。此外，我们将调查的作用，膝皮质通路的自发激活的方向域在视觉刺激的情况下。拟议实验的结果将有助于揭示皮质处理机制，可用于未来预防和治疗不同形式的中枢视觉障碍。

DESCRIPTION (provided by applicant): Accurate models of visual cortical function require a precise knowledge of how visual stimuli are represented within the cortex and the specific circuits that are involved in this representation. This knowledge is not only important to understand visual processing in the brain but it is also essential for the use of future cortical prosthesis that could provide vision to the blind through electrical microstimulation. Over the past years, there has been a great effort to investigate how line orientation and visual space are mapped within the primary visual cortex and how these representations are linked by different types of intracortical connections (horizontal connections, feedback connections and local intracortical connections). However, the equivalent measurements for geniculocortical connections are still missing. This gap in our knowledge is very significant because the geniculocortical connections are the main entrance of visual information to the brain and their functional organization is intimately related with the cortical representation of visual space. Lacking these data, current models of cortical function use very different patterns of geniculocortical connectivity, from those that assume a random distribution of the afferents to those that assume a neat alignment of the geniculate receptive fields along the preferred orientation of each cortical domain. In this proposal, we will use a new, powerful combination of multielectrode recording, optical imaging and neuronal tracer techniques to fill this important gap in knowledge and provide new experimental constraints to models of cortical function. Our experiments will reveal the organization of the geniculocortical pathway at the submillimeter scale and the role of this micro-organization in the representation of line orientation and visual space within the cortex. In addition, we will investigate the role of the geniculocortical pathway in the spontaneous activation of orientation domains in the absence of visual stimuli. The results of the proposed experiments will help to uncover mechanisms of cortical processing that could be used in the future to prevent and treat different forms of central visual disorders.