QUANTITATIVE STUDIES OF CORTICAL VISUAL PROCESSING

皮质视觉处理的定量研究

• 批准号: 6498346
• 负责人: DARIO L RINGACH
• 金额: $ 19.7万
• 依托单位: UNIVERSITY OF CALIFORNIA LOS ANGELES
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-02-01 至 2005-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6498346
• 关键词: Macaca fascicularis; action potentials; computer data analysis; conditioning; eye movements; head movements; lateral geniculate body; microelectrodes; motion perception; neural information processing; neuroanatomy; neurons; neurophysiology; orientation; psychophysics; space perception; visual cortex; visual stimulus

Our objective in this research is to reveal the neural circuitry generating novel response properties in the primate primary visual cortex (area V1). The experiments are designed to uncover the role cortical dynamics, suppressive signals, receptive field non-linearities, and functional intra- cortical connectivity play in the generation of neural response selectivity to visual stimulus attributes: orientation, direction of motion, spatial frequency, length, and width. Dynamics of Tuning: We will measure the dynamics of tuning selectivity in the different V1 layers using reverse correlation techniques. A recent improvement to this method (the inclusion of "blank" images) provides the means to determine the dynamics of excitation and inhibition, and to establish their contribution to the cell's response. Using this methodology, we will characterize the dynamics of tuning to orientation, direction of motion, spatial frequency, length, and width. The hypothesis that sharp tuning selectivity is present from the very beginning of the response will be tested. Role of Suppression: We will test the hypothesis that suppressive signals are involved in shaping the tuning selectivity of neural responses. To facilitate the detection of suppressive signals in extracellular recordings, we will measure tuning curves on top of a conditioning stimulus (two-dimensional noise) whose purpose is to elevate the activity of the cortex above the usually low spontaneous rates. We will seek evidence of inhibition: regions in the tuning curve where responses are depressed below the baseline activity. Spatio-temporal Linearity: We will test the hypothesis that simple cells behave as a linear spatio-temporal filter followed by a static non-Linearity. We will test the hypothesis that simple method that avoids the problems associated with the contribution of the output non-Linearity to the response. A goal of this experiment is to determine if quasi-linear mechanisms are sufficient to account for the tuning properties of simple cells. Functional connectivity: We will begin to explore the pattern of cortical interactions in the dimensions of space, orientation and spatial frequency. To achieve this goal, we will record simultaneously from pairs of neurons when their responses are elevated by the use of a conditioning stimulus. These experiments are designed to study, from multiple conceptual angles, the neural mechanisms generating cortical selectivity.. Taken together, these findings will advance our understanding of the computations and strategies used by V1 to process thalamic input.

本研究的目的是揭示灵长类动物初级视觉皮层（V1区）中产生新反应特性的神经回路。实验旨在揭示皮层动力学、抑制信号、感受野非线性和功能性皮质内连通性在视觉刺激属性（方向、运动方向、空间频率、长度和宽度）产生神经反应选择性中的作用。调优动态：我们将使用反向相关技术测量不同V1层中调优选择性的动态。最近对该方法的改进（包括“空白”图像）提供了确定兴奋和抑制动力学的方法，并确定它们对细胞反应的贡献。使用这种方法，我们将描述调整到方向，运动方向，空间频率，长度和宽度的动力学。从响应的一开始就存在尖锐调谐选择性的假设将得到检验。抑制的作用：我们将检验抑制信号参与形成神经反应的调谐选择性的假设。为了便于在细胞外记录中检测抑制信号，我们将在条件刺激（二维噪声）之上测量调谐曲线，其目的是将皮层的活动提高到通常较低的自发率之上。我们将寻找抑制的证据：调节曲线中反应低于基线活动的区域。时空线性：我们将测试简单细胞作为线性时空过滤器的假设，然后是静态非线性。我们将检验假设的简单方法，避免了与输出非线性对响应的贡献相关的问题。这个实验的目的是确定准线性机制是否足以解释简单细胞的调谐特性。功能连接：我们将开始探索空间、方向和空间频率维度上皮层相互作用的模式。为了实现这一目标，我们将同时记录成对神经元的反应，当它们的反应被使用条件反射刺激提高时。这些实验旨在从多个概念角度研究产生皮层选择性的神经机制。综上所述，这些发现将促进我们对V1处理丘脑输入的计算和策略的理解。