Intracortical Connections Underlying Cortical Function

[9221854]吉尔伯特大脑感觉皮层中的一个神经细胞被某个空间区域内的刺激激活，这个空间区域被称为细胞的“接受野”。来自体表触觉（体感系统）研究的证据表明，成年人的这些感受野在位置和大小上具有惊人的动态，而不是特定细胞的固定特征。主动感觉经验对定义感受野很重要；外周区的感觉丧失会减少该区域皮层细胞的接受野的大小，而持续的刺激会导致接受野的增加。最近的努力是确定当这些可塑性变化发生时，神经元通路中的连接是如何被修改的。这项研究是一种新的应用，与体感方法相似，但使用视觉皮层来利用视觉通路和皮层内连接的已知细节。在这里，研究了当部分视野不可见（暗点）时，视觉系统中感受野的变化。解剖学和药理学将用于检查与皮层的连接和内部的连接，以区分这些连接在皮层动力学中的贡献。这些研究将有助于阐明跨空间整合信息和皮层记忆的机制；重点是视觉处理，但其结果将对视觉神经科学以外的感觉神经科学和认知神经科学产生影响。＊＊＊

9221854 Gilbert A nerve cell in the sensory cortex of the brain is activated by stimuli that lie within a certain spatial area, called the "receptive field" of the cell. Evidence from work on the sense of touch on the body surface (somatosensory system) has shown that these receptive fields in adults are surprisingly dynamic in location and size, rather than having fixed characteristics for a given cell. Active sensory experience is important for defining the receptive field; a loss of sensation from the peripheral area reduces the size of receptive fields of cortical cells for that area, and persistent stimulation leads to an increase. Recent efforts have been to establish how connections in the neuronal pathway are modified when these plastic changes occur. This study is a novel application that parallels somatosensory approach, but uses the visual cortex to exploit known details of the visual pathway and intracortical connections. Here, changes in receptive fields in the visual system are studied when part of the visual field is made invisible (a scotoma). Anatomy and pharmacology will be used to examine connections to and within the cortex, to differentiate the contributions of such connections in the cortical dynamics. These studies will help elucidate the mechanisms of integrating information across space, and of cortical memory; the emphasis is on visual processing, but the results will have impact beyond visual neuroscience to sensory neuroscience in general, and to cognitive neuroscience. ***