Testing the roles of rat parietal and frontal cortices in a sensory decision task

描述（由申请人提供）：认知神经科学的中心目标是阐明决策背后的神经过程。即使是简单的决定，也往往依赖于超越即时感官环境的深思熟虑。因此，大脑需要允许信息在审议过程中随着时间的推移而组合的机制。本项目旨在利用最近开发的基于大鼠的审议决策模型来研究证据积累和决策承诺的神经过程。布罗迪实验室已经能够训练老鼠执行泊松点击积累任务，在这个任务中，老鼠根据比较两个扬声器（一个在老鼠的左边，另一个在它的右边）提供的听觉点击的数量来做出决定。研究表明，大鼠在完成这项任务时，会暂时整合由点击提供的感官证据。我们计划测试大鼠大脑的两个候选区域——额叶定向区（FOF）和后顶叶皮层（PPC）——在感官循证决策中发挥作用的程度。为了做到这一点，我们将在大鼠执行泊松点击积累任务时分别可逆地关闭每个区域，并测量对表现的影响。然后，我们将通过记录任务执行过程中的神经活动来测试这些区域的神经元是否代表了与证据积累和决策承诺相关的数量。最后，我们将使用决策过程的网络模型探讨这些区域发挥相似或不同作用的程度。该项目的实现将进一步加深我们对决策背后的神经过程的理解，并将大鼠作为未来研究这些问题的模式生物。了解这些大脑过程是开发针对高级脑功能障碍的有针对性、原则性治疗的关键一步。

DESCRIPTION (provided by applicant): A central goal of cognitive neuroscience is to elucidate the neural processes that underlie decision making. Even simple decisions often rely on deliberation that extends in time beyond the immediate sensory environment. Thus, the brain requires mechanisms that allow information to combine over time during the deliberative process. This project aims to exploit a recently developed rat-based model of deliberative decision-making to study the neural process that underlies accumulation of evidence and decision commitment. The Brody lab has been able to train rats to perform the Poisson Clicks Accumulation task, where rats make a decision based on comparing the number of auditory clicks presented on two speakers, one to the left of the rat, the other to its right. It has been shown that rats temporally integrate the sensory evidence provided by the clicks to perform this task. We plan to test the extent to which two candidate areas of the rat brain -- the frontal orienting fields (FOF) and posterior parietal cortex (PPC) -- play a role in sensory evidence-based decision making. To do this, we will reversibly inactivate each area separately while rats perform the Poisson Clicks Accumulation task and measure the effect on performance. We will then test whether neurons in these areas represent quantities related to the accumulation of evidence and decision commitment in their responses by recording neural activity during performance of the task. Finally, we will explore the extent to which these areas play similar or different roles using a network model of the decision process. Fulfillment of the aims of this project would further our understanding of the neural processes that underlie decision making and also develop the rat as a model organism for future studies of these questions. Understanding these brain processes is a key step towards developing targeted, principled treatments for disorders of higher brain function.