Neuronal Synchronization in the Visual Cortex of the Alert State

视觉的一个重要部分是模式识别，因此，包含许多视觉特征组合的视觉场景被认为是一个连贯的物体集合。构成图像中物体的局部特征集必须按照一定的标准进行分组，并相互分离，以防止不适当的特征连接。落在视网膜上的图像模式是由成千上万的神经细胞编码的，这些神经细胞向大脑发送信号，目前还不清楚大脑是如何整合这些信息的，这些信息被发送到视觉皮层的不同部分。一种被普遍接受的说法是，一些神经元对刺激的某些特征有选择性地做出反应，这些神经元的输出，即使是来自广泛分离的区域，也会汇聚到其他细胞上，这些细胞在复杂处理的分层组织中代表“特征检测器”。最近提出的另一种说法是，构成物体的综合特征是由一群共享同步活动的分布式神经元编码的。这两个过程都有一些证据，但后者背后的机制尚不清楚。在某些情况下，在猫和猴子的视觉皮层中已经观察到同步性。本研究确定了警觉动物的视觉皮层神经元同步放电的发生率、性质和空间范围，训练它们将眼睛固定在目标物体上。一种新型的多电极阵列记录了几个单个细胞对各种不同视觉刺激的同时反应。这些记录可以测试不同细胞的反应是如何相互关联的，以及几个不同皮层区域的细胞之间同步活动的程度。研究结果对于理解皮层功能、感觉神经科学和知觉心理学以及人工视觉系统的工程设计具有重要意义。

An important part of vision is pattern recognition, so that a visual scene that contains many combinations of visual features is perceived as a coherent collection of objects. Sets of local features making up the objects in an image must be grouped according to some criteria and segregated from one another to prevent inappropriate feature conjunctions. The pattern of images falling on the retina of the eye is encoded by many thousands of nerve cells sending signals into the brain, and it is not clear how the brain integrates the information that is sent to different parts of the visual cortex. One alternative commonly accepted is that some neurons are selectively responsive to certain features of a stimulus, and the outputs from these neurons, even from widely separate areas, converge on other cells that represent "feature detectors" in a hierarchical organization of complex processing. An alternative that has recently been raised is that the integrated features that make up objects are coded by a distributed population of neurons that share synchronous activity. There is some evidence for both processes, but the mechanisms underlying the latter remain unclear. Synchrony has been observed in some cases in the visual cortex of cats and monkeys. This study determines the incidence, properties and spatial extent of neuronal synchronous firing of neurons in the visual cortex of alert animals trained to fixate their eyes on a target object. A novel multiple electrode array records the simultaneous responses of several single cells to a variety of different visual stimuli. These recordings allow tests of how well responses from different cells are correlated, and to what degree synchronous activity is present among cells in several different cortical areas. Results will be important for understanding cortical function, for sensory neuroscience and perceptual psychology in general, and for potential use in the engineering design of artificial visual systems.