NRSA: Dynamic evaluation and control of decision making

描述(申请人提供)：我们计划研究人类基本的决策机制，包括感觉整合、假设检验和反应选择。我们还建议研究必要的控制机制，以调节这些决策过程，以响应不同的任务条件。我们建议使用事件相关脑成像(EEC)和功能磁共振成像(FMRI)来研究这些机制，以补充我们现有的行为结果。我们建议解决的主要问题是，非人类灵长类动物知觉决策背后的神经电路的简单“泄漏竞争累加器”(LCA)模型是否在人类大脑中实施；如果是这样，是否有证据表明我们开发的该模型的扩展可以解释与认知控制相关的表现适应--认知控制的一种干扰是大多数形式的精神障碍的核心。一个简单的感觉整合和假设检验的LCA模型，由非人类灵长类动物的直接神经元记录支持，表明在需要眼动反应的运动辨别任务中，顶内外侧沟(区域嘴唇)的神经元实施证据加权过程。此外，这一活动受到与可能结果相关的预期回报的影响。我们的假设是，这些现象反映了三个普遍的跨物种原则，它们支配着大多数任务中的所有反应方式：1)刺激-反应关联在加工的中间阶段在大脑中实施，将刺激识别阶段的输出转换为反应的启动；2)反应通道的这些初始阶段的斜坡活动不仅反映了反应前预期运动特征的提前准备，而且--关键的是--它反映了关于做出哪种反应的证据的实际权衡；3)在这个阶段，通过在持续的奖励和成本监测的基础上调节应用于该证据的阈值，实现了最简单形式的认知控制。我们建议使用运动辨别任务来检验这一假设，该任务涉及两种反应模式和对奖励偶发事件的多个操纵。这项任务非常适合将我们的非侵入性结果与直接记录数据相结合，而我们开发的这项任务所涉及的电路模型允许对模型所有组件中激活的时间分布进行强有力的定量预测。这项任务可能会提供一个窗口，了解由伤害或精神疾病引起的情感干扰通过不适当的阈值控制导致基本认知加工障碍的过程。这也可能解释了控制缺陷是如何导致奖赏处理受损的。

DESCRIPTION (provided by applicant): We propose to study basic human decision making mechanisms of sensory integration, hypothesis testing and response selection. We also propose to study the control mechanisms necessary for modulating these decision making processes in response to varying task conditions. We propose to investigate these mechanisms using event-related encephalography (EEC) and functional magnetic resonance imaging (fMRI) to complement our existing behavioral results. The major questions that we propose to address are whether a simple "leaky competing accumulator" (LCA) model of the neural circuitry underlying perceptual decision making in non-human primates is implemented in the human brain; and if so, whether evidence exists for an extension which we have developed of this model that can account for adaptations of performance associated with cognitive control -a disturbance of which is central to most forms of psychiatric disorder. A simple LCA model of sensory integration and hypothesis testing that is supported by direct neuronal recordings in non-human primates suggests that neurons in the lateral intraparietal sulcus (area LIP) implement an evidence-weighing process in the context of motion-discrimination tasks requiring eye-movement responses. Furthermore, this activity is modulated by the expected reward associated with possible outcomes. Our hypothesis is that these phenomena reflect three general, cross-species principles that govern all response modalities in most tasks: 1) stimulus-response associations are implemented in the brain at intermediate stages of processing that transform the outputs of stimulus identification stages into response initiation; 2) ramping activity in these initial stages of the response channels reflects not only the advance preparation of anticipated movement features prior to a response, but also - critically - it reflects the actual weighing of evidence about which response to make; 3) cognitive control in its simplest form is implemented at this stage by modulating the threshold applied to this evidence on the basis of continuous reward and cost monitoring. We propose to test this hypothesis using a motion-discrimination task involving two response modalities and multiple manipulations of reward contingency. This task is well suited for aligning our noninvasive results with direct recording data, and the model we have developed of circuits involved in this task allow strong, quantitative predictions about the temporal profile of activation in all of the model's components. This task may provide a window into the process by which disturbances of affect resulting from injury or psychiatric disease lead to disturbances of basic cognitive processing through inappropriate threshold control. It may also explain how control deficits lead to impaired reward processing.