Reentry and the problem of integrating multiple cortical areas: simulation of dynamic integration in the visual system.
Reentry and the problem of integrating multiple cortical areas: simulation of dynamic integration in the visual system.
复制标题
再入与多个皮质区域的整合问题：视觉系统中动态整合的模拟。
作者：
Giullo Tononi;Olaf Sporns;Gerald M. Edelman
对大脑皮层的研究，特别是视觉系统的研究，表明存在多个解剖学上分离的功能专门化的皮层区域。没有证据表明，这些由相互连接网络连接起来的区域，是由一个更高层次的中心协调的。然而，我们所感知的视觉图像似乎是统一和连贯的。在这篇文章中，我们解决这些意见所带来的整合问题。在我们以前的工作的扩展，我们开发了一个动态模型的再入。再入是一个并行和递归信号沿着有序的解剖连接，实现整合，通过引起建设性和相关的性质内和之间的地图。我们提出并测试了一个计算机模型模拟九个功能分离的视觉区域组织成三个流的形式，颜色和运动。该模型接收由不同形状和颜色的对象的相机图像组成的视觉输入。我们显示了专门的响应特性的领域在三个流。一个计算策略，涉及一个相位变量，明确表示分布在不同地区的数千个单位之间的短期时间相关性的动态。然后，我们说明了建设性的和相关的后果内的相互的内部和interareal连接的系统内的再入从心理物理学的两个例子：从运动和运动捕捉的形式生成。该模型通过短期相关性解决了所谓的“绑定问题”，短期相关性用于将模拟皮层区域内的相似对象特征联系起来，并将多个区域（包括非地形区域）中一个或多个对象的多个属性绑定起来。一体化产生于各专门领域内部和之间的合作效应。这些影响导致一个简单的输出，一个模拟的视觉聚焦反应，这是作为一个基础的条件反射。奖赏是通过激活一个显着性系统来介导的，该系统是以大脑中的弥散投射系统为模型的。因此，视觉皮层模型对输入刺激进行视觉聚焦反应，这需要对形状、颜色和位置进行动态结合和区分，以获得成功的表现。
Studies of the cerebral cortex, particularly those of the visual system, demonstrate the existence of multiple, anatomically segregated and functionally specialized cortical areas. There is no evidence that these areas, which are linked by a network of reciprocal connections, are coordinated by a higher-order center. The visual image that we perceive, however, seems to be unified and coherent. In this article, we address the problem of integration posed by these observations. In an extension of our previous work, we develop a dynamic model of reentry. Reentry is a process of parallel and recursive signaling along ordered anatomical connections that achieves integration by giving rise to constructive and correlative properties within and among maps. We present and test a computer model simulating nine functionally segregated visual areas organized into three streams for form, color, and motion. The model receives visual input consisting of camera images of objects of different shapes and colors. We show the specialized response properties of the areas in the three streams. A computational strategy involving a phase variable is introduced to represent explicitly the dynamics of short-term temporal correlations among thousands of units distributed across different areas. We then illustrate constructive and correlative consequences of reentry within a system of reciprocal intra- and interareal connections by two examples taken from psychophysics: generation of form from motion and motion capture. The model solves the so-called "binding problem" through short-term correlations, which serve to link similar object features within a simulated cortical area and to bind multiple attributes of one or more objects across several areas, including a nontopographic one. Integration emerges from cooperative effects within and among the specialized areas. These effects lead to a simple output, a simulated foveation response, that is used as a basis for conditioning. Reward is mediated by the activation of a saliency system that is modeled on diffuse projection systems in the brain. As a result, the visual cortical model carries out foveation responses to input stimuli that require the dynamic conjunction and discrimination of form, color, and location for successful performance.