Models of Correlation Based Neural Development

描述（改编自申请人的摘要）：这项工作的长期目标是了解大脑皮层的电路和其活动依赖性发展的规则。猫的初级视皮层（V1）被研究作为一个模型系统，更普遍地了解皮层。计算建模用于确定哪些电路模式可以解释V1神经元的功能反应特性，以及哪些活动指示的突触修饰规则可以产生这些电路模式的自组织。大脑皮层回路是大多数感官知觉、大部分运动规划和大多数与人类智力相关的高级认知功能的基础，因此对皮层回路及其发展的理解将极大地影响我们对正常和患病大脑功能的理解。特别是，对V1回路和发育的理解将影响我们对正常视力和视力中枢疾病（如弱视和斜视）的理解。 这项工作的具体目标是开发生物可识别和可测试的模型的电路层4，输入受体层，猫V1和该电路的发展。发展的研究将测试的假设，尖峰定时依赖可塑性（STDP），基于自发的活动模式，存在于视觉经验影响发展，可以解释V1感受野和功能电路的组织。一个特别的重点将是了解方向选择性和相关的皮层电路的发展。成熟电路的研究将建立在以前的工作表明，一个“相关性为基础的”电路，其中兴奋性细胞往往项目的细胞具有相似或良好相关的感受野（重叠的ON-和OFF-亚区）和抑制性细胞往往项目的细胞大致相反或相关或反相的感受野，可以解释V1层4细胞的许多功能反应特性。这项工作将被扩展到将新的实验结果的作用，电压噪声在V1的反应，方向untuned复杂的抑制性神经元，和突触抑制V1的反应。它还将扩展到解决方向选择性，通过将输入神经元的时间响应特性的多样性，并通过扩展基于空间相关性的电路的电路的时空相关性。

DESCRIPTION (adapted from applicant's abstract): The long-term goal of this work is to understand the circuitry of the cerebral cortex and the rules underlying its activity-dependent development. Primary visual cortex (V1) of the cat is studied as a model system for understanding cortex more generally. Computational modeling is used to determine what patterns of circuitry can account for the functional response properties of V1 neurons and what rules of activity-instructed synaptic modification can yield the self-organization of these patterns of circuitry. Cerebral cortical circuitry underlies most sensory perception, much of motor planning, and most of the higher cognitive functions associated with human intelligence, so an understanding of cortical circuitry and its development will strongly impact our understanding of both normal and diseased brain function. In particular, understanding of V1 circuitry and development will impact our understanding of normal vision and of central diseases of vision such as amblyopia and strabismus. The specific aims of this work are to develop biologically identifiable and testable models of the circuitry of layer 4, the input-recipient layer, of cat V1 and of the development of that circuitry. Studies of development will test the hypothesis that spike-timing-dependent plasticity (STDP), based on spontaneous patterns of activity that exist before visual experience impacts development, can account for the organization of V1 receptive fields and functional circuits. A particular focus will be to understand the development of direction selectivity and of the associated cortical circuitry. Studies of the mature circuit will build on previous work showing that a "correlation-based" circuit, in which excitatory cells tend to project to cells with similar or well correlated receptive fields (overlapping ON- and OFF-subregions) and inhibitory cells tend to project to cells with roughly opposite or anticorrelated or antiphase receptive fields, can account for many of the functional response properties of V1 layer 4 cells. This work will be extended to incorporate new experimental findings on the roles of voltage noise in V1 responses, of orientation-untuned complex inhibitory neurons, and of synaptic depression in V1 responses. It will also be extended to address direction selectivity by incorporating diversity of temporal response properties of input neurons and by extending the spatial correlation-based circuitry to circuitry based on spatiotemporal correlations.