Investigating prefrontal contributions to source and temporal order memory for faces and words

前额叶(PFC)由人类额叶的大部分组成，被认为对调节受控的、灵活的、更高的认知能力是重要的，这些能力将人类与其他灵长类区分开来。其中一个较高的认知能力是对我们过去个人经历的高度详细的描述进行编码和回忆的能力。这种类型的记忆称为情节记忆(EM)。神经成像研究发现，在提取项目信息(再认记忆)、与个人过去有关的空间/知觉细节(来源记忆)和与个人过去有关的时间细节(时间顺序记忆)时，PFC参与的区域差异。然而，对于这些不同的PFC区域分别贡献了哪些认知过程，以及这些过程本质上是特定于EM的，还是与更一般的认知控制或执行过程有关，例如：记忆形成和提取过程中基于规则的信息组织(策略组织)、任务目标的在线维持、反应协调和反应监控等，仍存在很大争议。当前研究项目的目标是调查PFC对EM提取的特定区域的贡献。具体地说，这项研究将使用一种创新的大脑成像技术：事件相关功能磁共振成像，以检查健康成年志愿者在执行言语和非言语(面部)刺激的来源、时间顺序和项目记忆任务时，PFC活动的在线区域变化。提取时呈现的刺激数量和所需的运动反应数量将在不同任务之间进行参数控制，并将分别控制战略组织和反应协调过程。用于反应监测过程的刺激运动反应控制的组合参数操作。这一提议的结果将有助于确定PFC中是否有与前述执行过程有差异的亚区，而且是一致的，跨背景记忆任务和跨刺激类型。

The prefrontal cortex (PFC) comprises most of the human frontal lobes and is known to be important for mediating controlled, flexible, higher cognitive abilities that differentiate human beings from other primates. One such higher cognitive ability, is the ability to encode and recollect highly detailed accounts of our past personal experiences. This type of memory is referred to episodic memory (EM). Neuroimaging studies have identified regional differences in PFC involvement during the retrieval of: item information (recognition memory), spatial/perceptual details pertaining to one's personal past (source memory) and temporal details pertaining to one's personal past (temporal order memory), respectively. However, there is much debate over what cognitive processes these distinct PFC regions contribute, respectively, and whether these processes are EM-specific in nature, or related to more general cognitive control or "executive" processes, such as: rule-based organization of information during memory formation and retrieval(strategic organization), on-line maintenance of task goals, response coordination and response monitoring, to name a few. The goal of the current research project is to investigate the region-specific contributions of PFC to EM retrieval. Specifically, this research will use an innovative brain imaging technique: event-related fMRI, to examine on-line regional changes in PFC activity as healthy adult volunteers perform source, temporal order, and item memory tasks for verbal and non-verbal (face) stimuli. The number of stimuli presented at retrieval, and the number of motor responses required, will be parametrically manipulated across tasks, and will control for strategic organization and response coordination processes, respectively. The combined parametric manipulation of stimulus+motor response controls for response monitoring processes. Results from this proposal will help determine whether there are subregions in PFC that are differentially related to the aforementioned executive processes,  consistently, across context memory tasks and across stimulus type.