Contextual modulation of orientation specificity in V1

V1 方向特异性的上下文调节

• 批准号: 6897366
• 负责人: David C Lyon
• 金额: $ 0.97万
• 依托单位: SALK INSTITUTE FOR BIOLOGICAL STUDIES
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-09-26 至 2005-09-25
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6897366
• 关键词: brain electrical activity; brain imaging /visualization /scanning; cats; confocal scanning microscopy; fluorescent dye /probe; microelectrodes; neural information processing; neuroanatomy; postdoctoral investigator; vision; visual cortex

DESCRIPTION (provided by applicant): The aim of this proposal is to identify the underlying intrinsic mechanisms of contextual modulation in primary visual cortex (V1). Though the basic drive of orientation selectivity of V1 neurons is known to derive from retinal relays of the lateral geniculate nucleus (LGN), modulation of this classical receptive field (CRF) is generated through lateral long-range connections within V1. This surround modulation can either suppress or enhance the response of a neuron to its CRF. Previous work from the Sur lab and others has shown that the direction of the modulation depends on the orientation of the surround and the contrast of the CRF. Furthermore, orientation preference maps are arranged so that transitions between preferred orientation domains can be smooth or fractured (where incongruent orientation domains are found adjacent to each other). There are indications that long-range inputs to these fracture sites come from an in-homogenous array of other orientation domains, whereas smooth, or iso-orientation domains are known to receive lateral connections primarily from like iso-orientation domains. The proposed experiments will use optical imaging to identify fracture sites for fluorescent tracer injections, and two-photon microscopy will be used to identify the resulting clusters of labeled cells in V1. By matching the sites of labeled cells with the orientation preference map we can define specifically which regions provide modulatory input. With this information we can discreetly stimulate these regions with optimal orientation displays and systematically measure the effects on the CRF.

描述（由申请人提供）：本提案的目的是确定初级视觉皮层（V1）中背景调制的潜在内在机制。虽然V1神经元的方向选择性的基本驱动力是来自外侧膝状体核（LGN）的视网膜中继，但这种经典感受野（CRF）的调制是通过V1内的外侧长程连接产生的。这种环绕调制可以抑制或增强神经元对其CRF的反应。苏尔实验室和其他人以前的工作表明，调制的方向取决于环绕的方向和CRF的对比度。此外，取向偏好图被布置成使得优选取向域之间的过渡可以是平滑的或断裂的（其中发现不一致的取向域彼此相邻）。有迹象表明，这些骨折部位的长距离输入来自其他方向域的非均匀阵列，而已知平滑或等方向域主要从等方向域接收横向连接。拟议的实验将使用光学成像来识别荧光示踪剂注射的骨折部位，双光子显微镜将用于识别V1中标记细胞的结果簇。通过将标记细胞的位点与取向偏好图相匹配，我们可以明确定义哪些区域提供调节性输入。有了这些信息，我们可以谨慎地用最佳方向显示刺激这些区域，并系统地测量对CRF的影响。