Neural Basis of Categories

描述（由申请人提供）：类别是认知的基础。想象一下，如果我们不能抽象经验的“本质”，而必须重新学习每一个独特的对象和情况。我们可能会出现类似于自闭症和精神分裂症等神经精神疾病的功能障碍，其特征是从经验中概括和提取意义的能力受损。虽然我们对自下而上的感觉信息处理的皮层组织有很多了解，但对不同皮层区域在自上而下的处理过程中的各自作用，特别是分类过程，几乎一无所知。这是因为很少有神经生理学研究直接比较了不同脑区的类别的神经相关性，重要的是，没有神经生理学研究操纵了决定分类水平的属性。我们将这样做，同时直接比较前额叶皮层（PFC）和外侧顶内区（LIP）的神经活动，人类和猴子的研究表明，这两个皮层区域参与视觉分类。我们将测试的假设，即PFC发挥核心作用，在提取学习的类别或PFC或LIP将发挥主导作用，根据类别的需求水平的分类。我们将同时记录两个已知具有类别PFC和LIP的神经相关性的大脑区域，在一个已知激活人类两个区域的任务中（点模式分类）。猴子会对由任意点模式的扭曲原型形成的类别样本进行分类。因为点模式可以参数化地变化，我们可以操纵基本的类别属性（抽象性、复杂性和可供选择的类别决策的数量）。由于我们对这些操作如何影响类别的神经相关性几乎一无所知，因此任何结果模式都将提供信息，并提供对大脑为世界添加意义的基本机制的洞察。

DESCRIPTION (provided by applicant): Categories are a foundation of cognition. Imagine if we could not abstract the "essence" of experiences and had to learn anew about every unique object and situation. We would probably have dysfunctions like those seen in neuropsychiatric disorders like autism and schizophrenia, which are marked by an impaired ability to generalize and extract meaning from experience. While a great deal is known about the cortical organization of the processing of bottom-up sensory information, virtually nothing is known about the respective roles of different cortical areas in top-down processing, particularly categorization. This is because few neurophysiological investigations have directly compared neural correlates of categories across brain areas and, importantly, no neurophysiological study has manipulated the attributes that determine the level of categorization. We will do so while directly comparing neural activity in the prefrontal cortex (PFC) and lateral intraparietal area (LIP), two cortical areas that human and monkey studies indicate are engaged during visual categorization. We will test the hypothesis that the PFC plays the central role in extracting learned categories or that either the PFC or LIP will play the leading role in categorization depending on the level of category demand. We will record simultaneously two brain regions known to have neural correlates of categories the PFC and LIP in a task known to activate both areas in humans (dot pattern categorization). Monkeys will classify category exemplars formed by distorting prototypes of arbitrary dot patterns. Because dot patterns can be parametrically varied, we can manipulate fundamental category properties (abstractness, complexity, and number of alternative category decisions). Because virtually nothing is known about the how these manipulations affect the neural correlates of categories, any pattern of results will be informative and provide insight into the fundamental mechanisms by which the brain adds meaning to the world.