Neuroimaging of Executive Processing

描述（由申请人提供）：执行流程有助于灵活的、自上而下的对人类行为的控制。包括前额叶皮层（PFC）、前扣带皮层和顶叶皮层在内的大脑区域网络被认为是执行处理的中心。神经影像学和病变研究表明，这些区域在基于环境的行为选择或增强中起作用。本实验将使用功能性磁共振成像（fMRI）来研究反应选择、反馈和奖励评估以及目标导向行为控制的神经机制。这项建议有三个具体目标。首先，它试图阐明背侧PFC （dlPFC）在行为控制中的作用，以验证执行功能增强刺激-反应偶然性而不是反应本身的假设。所提出的实验操作信息的数量，每个刺激在一个序列有助于学习决策规则或准备所需的反应。其次，研究了腹内侧PFC （vmPFC）在反应和奖励之间的偶然性增强中的作用。本实验通过操纵与不同刺激和不同时间点的反应相关的奖励期望来验证vmPFC支持解决奖励-反应联系不确定性的假设。第三，通过研究奖励不确定性对决策过程的影响，研究前额叶系统之间的相互作用。一些刺激与未来回报的不确定性有关，而另一些则与确定的结果有关。实验验证了vmPFC奖励系统活动增加导致dlPFC控制系统活动减少的假设。该研究计划将对理解人类执行过程产生重大影响，包括选择、决策和工作记忆组成部分。更好地了解这些过程将导致进一步改善以执行功能或行为选择受损为特征的神经和精神疾病的临床补救（例如，额叶损伤、精神分裂症、帕金森病）。

DESCRIPTION (provided by applicant): Executive processes facilitate the flexible, top-down control of human behavior. A network of brain regions including prefrontal cortex (PFC), anterior cingulate cortex, and parietal cortex is thought to be central for executive processing. Neuroimaging and lesion studies have suggested that these regions play a role in selection or potentiation of behavior based upon context. The experiments detailed in this proposal will use functional magnetic resonance imaging (fMRI) to investigate the neural mechanisms of response selection, evaluation of feedback and rewards, and the goal-directed control of behavior. This proposal has three specific aims. First, it seeks to elucidate the role of dorsolateral PFC (dlPFC) in behavioral control, to test the hypothesis that executive functions potentiate sets of stimulus-response contingencies rather than responses themselves. The proposed experiments manipulate the amount of information each stimulus in a sequence contributes either to learning a decision rule or to preparing a needed response. Second, it investigates the role of ventromedial PFC (vmPFC) in the potentiation of contingencies between responses and rewards. The proposed experiments manipulate the reward expectation associated with different stimuli and with responses at different points in time, to test the hypothesis that vmPFC supports the resolution of uncertainty about reward-response links. Third, it investigates the interaction between prefrontal systems by examining the influence of reward uncertainty upon decision processes. Some stimuli are associated with uncertainty in future rewards, while others are associated with certain outcomes. The experiments test the hypothesis that increasing activity in vmPFC reward systems results in decreased activity in dlPFC control systems. The proposed research program will have a significant impact upon the understanding of human executive processing, including selection, decision, and working memory components. A better understanding of these processes will lead to further improvements in clinical remediation of neurological and psychiatric disorders characterized by impairments in executive function or behavioral selection (e.g., frontal lobe damage, schizophrenia, Parkinson's disease).