Functional Plasticity in Adult Visual Cortex

成人视觉皮层的功能可塑性

• 批准号: 6943840
• 负责人: Yang DAN
• 金额: $ 29.62万
• 依托单位: UNIVERSITY OF CALIFORNIA BERKELEY
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-09-01 至 2008-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6943840
• 关键词: cats; clinical research; computer simulation; conditioning; electrophysiology; human subject; neural plasticity; neurophysiology; psychophysics; stimulus /response; visual cortex; visual perception; visual stimulus

DESCRIPTION (provided by applicant): Activity-dependent plasticity is essential for development and function of the nervous system. In the mammalian neocortex, sensory stimuli play crucial roles in shaping the circuitry and function, which may be largely mediated by activity-dependent synaptic modification. Although at each level - synaptic, circuitry, and functional - cortical plasticity has been studied extensively, the causal relationship between activity-induced modifications at different levels remains to be firmly established. Our goal is to bridge the understanding of cortical plasticity at these levels. In recent studies, we have demonstrated that asynchronous visual stimuli (1-2 min) can induce shifts in adult cortical receptive fields (RFs) and in human spatial perception in a manner consistent with spike-timing-dependent plasticity (STDP), a powerful synaptic learning rule widely observed among excitatory synapses in the brain. In the proposed study we will further examine the functional modifications of adult visual cortex mediated by STDP, using a combination of electrophysiological and psychophysical experiments and computational modeling. There are three specific aims, examining the mechanism and functional significance of the cortical plasticity. In Aim 1, we will test whether RF and perceptual modifications can be induced by brief periods (seconds) of visual conditioning, a possibility suggested by recent studies in cortical slices. Such rapid plasticity may operate more frequently under natural conditions, and this experiment will provide a basis for our subsequent studies of cortical modifications induced by natural stimuli. In Aim 2, we will investigate the neuronal circuitry underlying the functional modification. We will first measure the interocular transfer of the effect to determine whether it is cortical in origin. We will then examine systematically the dependence of the cortical modification on conditioning parameters (orientation, luminance polarity, timing, and location of conditioning stimuli) and on other properties of the recorded neuron (simple/complex classification, laminar location, binocularity, and direction selectivity) to further determine the underlying circuitry. In Aim 3, we will directly assess the functional relevance of the plasticity by measuring cortical modification induced by motion stimuli and by natural scenes containing motion signals. Together, these studies are likely to provide significant new insights into the functional implications of activity-dependent synaptic plasticity at the levels of cortical circuitry, RF properties, and visual perception.

描述（由申请人提供）：与活动有关的可塑性对于神经系统的发展和功能至关重要。在哺乳动物的新皮层中，感觉刺激在塑造电路和功能中起着至关重要的作用，这可能在很大程度上是由活性依赖性突触修饰介导的。尽管在每个级别 - 突触，电路和功能性 - 皮质可塑性已经进行了广泛的研究，但是在不同级别上，活动诱导的修饰之间的因果关系尚待确定。我们的目标是在这些水平上弥合对皮质可塑性的理解。在最近的研究中，我们已经证明，异步视觉刺激（1-2分钟）可以诱导成人皮质接受场（RFS）和人类空间感知的转移，其方式与依赖性依赖性可塑性（STDP）一致，这是一种强大的突触学习规则，在大脑的兴奋性突触中广泛观察到。在拟议的研究中，我们将进一步研究由STDP介导的成年视觉皮层的功能修饰，并结合电生理学和心理物理实验和计算建模。有三个特定的目的，研究了皮质可塑性的机制和功能意义。在AIM 1中，我们将测试RF和感知修改是否可以通过短期（秒）的视觉调节诱导，这是最近在皮质切片中的研究所暗示的。这种快速的可塑性可能在自然条件下更频繁地运行，该实验将为我们随后对自然刺激引起的皮质修饰研究提供基础。在AIM 2中，我们将研究功能修饰的基础神经元电路。我们将首先测量效应的眼内转移，以确定其是否是皮质的。然后，我们将系统地检查皮质修饰对条件参数的依赖性（方向，亮度极性，时间和调节刺激的位置）以及记录神经元的其他特性（简单/复杂分类，层状分类，层状位置，双向线索和方向选择性），以进一步确定下面的电路。在AIM 3中，我们将通过测量由运动刺激引起的皮质修饰和包含运动信号的自然场景来直接评估可塑性的功能相关性。总之，这些研究可能会提供有关在皮质回路，RF特性和视觉感知水平上活性依赖性突触可塑性的功能意义的重要新见解。