Functional Organization of Visual Cortex

视觉皮层的功能组织

• 批准号: 7032941
• 负责人: DAVID FITZPATRICK
• 金额: $ 37.6万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1987
• 资助国家: 美国
• 起止时间: 1987-09-01 至 2010-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7032941
• 关键词: Scandentia; behavioral /social science research tag; brain mapping; cell type; developmental neurobiology; histology; intercellular connection; neural information processing; neuronal transport; single cell analysis; tissue /cell preparation; visual cortex; visual pathways; visual perception; visual stimulus

DESCRIPTION (provided by applicant): This proposal continues ongoing analysis of the mechanisms by which neural circuits in primary visual cortex represent stimulus features. Work from this lab has been exploring the contribution of feedforward projections from layer 4 and recurrent connections within layer 2/3 to the orientation selective responses of layer 2/3 neurons. The experiments proposed here will expand on this line of inquiry by investigating how other properties of the stimulus such as luminance and color, and how multiple stimulus orientations, are represented in the responses of orientation selective layer 2/3 neurons. As demonstrated by preliminary results, changes in background luminance exert a powerful suppressive influence over the response of orientation tuned layer 2/3 neurons, dramatically delaying the emergence of a tuned response and virtually eliminating an ongoing tuned response. The first aim explores the feedforward and recurrent mechanisms that contribute to this effect. The second aim probes whether the mechanism that is responsible for representing edge orientations at short wavelengths of light is distinct from that responsible for representing edge orientations at longer wavelengths. Specifically, experiments will test whether the short wavelength-sensitive cone system, which preliminary results show is capable of driving orientation selective responses in layer 2/3, does so independent of feedforward inputs from layer 4. Finally, the third aim examines how two edge orientations presented simultaneously are represented in the responses of layer 2/3 neurons. Preliminary results demonstrate that the addition of a second grating stimulus alters the response of layer 2/3 neurons in a highly predictable fashion; the mechanisms that underlie these effects will be explored. The proposed experiments employ intracellular, extracellular, and optical recording techniques to probe these issues at both the single cell and population level. Taken together they should provide new insights into the functional organization of local circuits in visual cortex, information that is crucial for understanding the neural basis of visual perception.

描述（由申请人提供）：该提案继续对主要视觉皮层中神经回路代表刺激特征的机制进行持续的分析。该实验室的工作一直在探索第4层和第2/3层内部连接的前馈投影的贡献，以及第2/3层神经元的方向选择性响应。此处提出的实验将通过研究刺激的其他特性（例如亮度和颜色）的其他特性，以及如何在方向选择性层2/3神经元的响应中表示多种刺激方向。正如初步结果所证明的那样，背景亮度的变化对定向调谐层的2/3神经元的响应产生了强大的抑制作用，从而极大地延迟了调谐反应的出现，并且实际上消除了正在进行的调谐反应。第一个目的探讨了有助于这种效果的饲喂和反复的机制。第二个目标探测了负责在光的短波长下代表边缘方向的机制是否不同于负责在较长波长下表示边缘方向的机制。具体而言，实验将测试初步结果表明的短波长敏感锥系统是否能够在第2/3层中推动定向选择性响应，这确实与第4层的进料输入无关。最后，第三个目标研究了在第2/3神经元的第2/3层响应中表现出的两个边缘方向。初步结果表明，第二个光栅刺激的添加以高度可预测的方式改变了第2/3层神经元的响应。将探索这些效果的基础的机制。提出的实验采用细胞内，细胞外和光学记录技术来探测单个细胞和人群水平的这些问题。综上所述，他们应该为视觉皮层中当地电路的功能组织提供新的见解，这对于理解视觉感知的神经基础至关重要。