ATTENTION SHIFTING HYPOTHESIS FOR THE BASAL GANGLIA

本项目将定义基底神经节在选择性 注意力，并出于对新兴 了解额叶-纹状体回路 虽然帕金森患者 有运动问题，神经解剖学的考虑表明， 基底神经节形成的计算的一般描述。 一 神经回路始于背外侧前额叶皮层，这一区域通常 被认为有助于工作记忆的颜色的独立领域， 形式和空间。 神经回路以一种 方式与来自运动性前部区域的电路类似， 这表明基底神经节对每一个神经元执行相同的计算， 电路. 我们提出了一个注意力计算，其中的基础 神经节参与建立、维持和转换集合。 对这一理论的决定性检验将来自一个证明， 帕金森病患者和额叶卒中患者的大脑皮层 建立和转换涉及颜色和形式的集合。 我们实验室和其他实验室对帕金森患者的先前研究 尚未提供证据证明基底神经节在转移中的作用 空间注意力，或在运动序列之间转换。 因此我们 区分注意力和选择性的偏置功能 功能，并表明早期的研究未能确定 基底神经节的注意功能是由于他们使用偏置 范例 这些范例提示一个刺激特征或维度， 而其他的则在它们意外发生时仍然相关。 另一方面，选择要求不相关的维度 积极阻止，以防止他们在一个给定的响应激活 任务上下文。 由于基底神经节既含有抑制性神经元， 兴奋子电路，这种双重特性符合我们的建议 基底神经节涉及相关尺寸的选择， 不相关的抑制。 基底神经节注意理论 将在帕金森病患者中测试额-纹状体回路内的转换 患者的药物状态的操作，并在患者 在一系列实验中， 注意颜色和形式。

This project will define the role of the basal ganglia in selective attention, and is motivated by a consideration of an emerging understanding of fronto-striatal circuits. Although Parkinson patients have motor problems, consideration of neuroanatomy suggests a more general description of the computation formed by the basal ganglia. One neural circuit begins in dorsolateral prefrontal cortex, an area often thought to subserve working memory for the separate domains of color, form, and space. The circuit courses through the basal ganglia in a manner not unlike that for circuits coming from motoric frontal regions, suggesting that the basal ganglia performs the same computation for each circuit. We propose an attentional computation in which the basal ganglia are involved in establishing, maintaining, and switching set. A decisive test of the theory would come from a demonstration that Parkinson patients and frontal stroke patients have impairment in establishing and switching sets involving color and form. Previous studies of Parkinson patients in our laboratories and others have not provided evidence for a role of the basal ganglia in shifting spatial attention, or shifting between movement sequences. We therefore draw a distinction between biasing functions of attention and selective functions, and suggest that the failure of earlier studies to identify attentional functions for basal ganglia was due to their use of biasing paradigms. These paradigms cue for one stimulus feature or dimension, leaving others as still relevant should they unexpectedly occur. Selection, on the other hand, requires that irrelevant dimensions be actively blocked to prevent their activation of a response in a given task context. Since the basal ganglia contain both inhibitory and net excitatory subcircuits, this dual characteristic fits with our proposal that the basal ganglia involves both selection of relevant dimensions and inhibition of irrelevant ones. The theory of basal ganglia attention switching within fronto-striatal circuits will be tested in Parkinson patients by manipulations of medication state, and in patients with infarcts of dorsolateral prefrontal cortex in a series of experiments on attention to color and form.