CRCNS: Attentional Selection and Perceptional Organization

项目摘要 拟议的研究解决了感知组织如何与 视觉系统中的注意力选择虽然这些问题经常被考虑， 我们认为它们是紧密相连的，事实上可能有一个共同的神经系统。 衬底我们认为图形-背景组织的神经机制，即， 视觉对象边界的神经表征依赖于神经元回路， 来表示这些对象是否被关注。我们将研究单细胞活性， 纹外皮层有多个电极这些数据将用于约束大规模的详细 神经元回路的模型。将追求三个具体目标。 第一个目标是建立注意无关图形-背景组织的模型， 皮质区V2。在以前的工作中，我们已经开发了一个图形-背景分离模型， 解释边界所有权选择性的机制。这个模型只能解释 平均放电率的变化。新模型将基于单神经元模型， 包括尖峰，因此能够模拟边界所有权的幅度和时间过程 信号以及神经元之间的成对尖峰序列相关性。 第二个目的是研究图形-背景结构的短时记忆。我们将执行多个 在区域V2中同时进行单个单元记录，以表征最近观察到的滞后现象 边界所有权编码的影响。我们还将记录更高的纹外区（V3和V4） 由于边界所有权选择性的快速时间进程， 通过白色物质的连接。这些电生理记录将补充 随着边境所有权信号的持续性和滞后性模型的发展。我们 将通过引入更复杂的单神经元模型来扩展尖峰神经网络模型 这可以解释滞后效应的机制。 第三个目的是研究选择性注意与图形-背景机制的相互作用 组织和功能绑定。我们建议前景图形的侧面选择性 在纹外皮层中观察到的现象来自于细胞分组的反复偏倚，而后者 也是用来用心挑选人物的。我们将从单个细胞和成对细胞中记录， 研究选择性注意对边界归属的影响 选择性。这些记录将与自上而下的选择性相互作用的模型相结合。 注意人物背景组织。我们将扩展脉冲神经网络模型 在目标1下制定，包括选择性注意。该模型将解释利率效应， 结合条件和注意状态变化下的成对相关函数。 拟议的研究将有助于我们了解一些最基本的 灵长类动物的视觉机制，这是重要的了解正常和受损 人类的视力。从这个项目中获得的见解将有助于理解 认知障碍的神经基础，如阅读障碍和偏侧忽视。

Project Summary The proposed research addresses the question of how perceptual organization interfaces with attentional selection in the visual system. While these questions are frequently considered separate, we believe that they are closely connected and may in fact share a common neural substrate. We propose that the neuronal mechanisms of figure-ground organization, that is, the neural representation of the borders of a visual object, relies on neuronal circuitry that is also used to represent whether these objects are attended or not. We will study single cell activity with multiple electrodes in extrastriate cortex. These data will be used to constrain large-scale detailed models of the underlying neuronal circuitry. Three specific aims will be pursued. The first Aim is to model the mechanisms of attention-independent figure-ground organization in cortical area V2. In previous work, we have developed a model of figure-ground segregration that explains mechanisms underlying border ownership selectivity. The model can only explain changes in mean firing rates. The new model will be based on a model of single neurons that includes spiking and will thus be able to model amplitude and time course of the border ownership signals as well as pairwise spike train correlation between neurons. The second Aim is to study short-term memory for figure-ground structure. We will perform multiple simultaneous single-unit recordings in area V2 to characterize the recently observed hysteresis effects in border ownership coding. We will also record in higher extrastriate areas (V3 and V4) since the fast time course of border ownership selectivity makes it likely that it is imparted by connections through the white matter.These electrophysiological recordings will be complemented with the development of a model of persistence and hysteresis of border ownership signals. We will expand the spiking neural network model by introducing more complex single-neuron models that can explain the mechanisms underlying the hysteresis effects. The third Aim is to study how selective attention interacts with mechanisms of figure-ground organization and feature binding. We suggest that the selectivity to side of foreground figure observed in extrastriate cortex arises from a recurrent bias from grouping cells, and that the latter are also used to attentively select the figure. We will record from single cells and pairs of cells in extrastriate area V2 and study the influence of selective attention on border ownership selectivity.These recordings will be combined with a model of the interaction of top-down selective attention with figure ground organization. We will expand the spiking neural network model developed under Aim 1 to include selective attention. The model will explain rate effects and pairwise correlation functions under a variation of binding conditions and attentional states. The proposed research will contribute to our understanding of some of the most fundamental mechanisms of primate vision which is of importance for understanding both normal and impaired vision in humans. The insight gained from this project will contribute to the understanding of the neural basis of cognitive disorders such as dyslexia and hemi-neglect.