Remembering amidst competition: neural systems for reactivation and selection

描述（由申请人提供）：有效的情景记忆系统的基础是选择性记忆的能力-能够将注意力集中在相关记忆上而排除不相关的记忆。虽然人们认为前额叶皮层（PFC）在竞争记忆中的选择中起着关键作用，但关于竞争如何在神经水平上表现以及PFC如何与后皮质部位相互作用以实现选择仍然存在相当大的模糊性。该提案旨在促进理解竞争如何影响支持记忆“重新激活”的皮层区域的处理，以及这些区域的信号如何与特定PFC子区域的参与相关。第一个实验将评估记忆竞争在处理事件的感知元素并在提取过程中重新激活的区域中的表现。据推测，在这些感知区域的信号的保真度将与PFC的参与。第二个实验将评估PFC机制的一般性，解决竞争，正式测试竞争检索和那些管理知觉决策机制之间的重叠。最后，第三个实验将评估检索的适应性质量，探索作为先前检索行为的结果而出现的再激活偏差。在这些实验中的每一个中，实验范例将被构造成使得相关（目标）和不相关（干扰）记忆总是来自由不同的感知皮层区域处理的视觉类别（即，面孔和场景）。这种方法将允许直接比较与目标和干扰物相关的再激活，因此对于测量PFC参与和从感知皮层区域传播的信号之间的关系至关重要。这些实验追求旨在为与在各种临床和非临床状态中经常观察到的记忆失败相关的更多应用实验问题奠定基础。总结：目前的建议旨在使用功能性MRI来更好地了解在神经水平上，情景记忆之间的竞争是如何经历和解决的。这项工作强调了这样一个事实，即记忆经常失败，不是因为信息没有在第一时间学习，而是因为检索操作被竞争所淹没。所获得的见解与衰老和痴呆症（特别是阿尔茨海默氏症类型）相关的记忆障碍和损伤具有明显且关键的相关性。

DESCRIPTION (provided by applicant): Fundamental to an efficient episodic memory system is the ability to remember selectively-to be able to focus attention on relevant memories at the exclusion of irrelevant memories. While it is thought that prefrontal cortex (PFC) plays a critical role in selecting among competing memories, there remains considerable ambiguity concerning how competition is represented at a neural level and how PFC interacts with posterior cortical sites to achieve selection. This proposal seeks to advance understanding of how competition impacts processing in the cortical regions that support 'reactivation' of memories and how signals from these regions relate to engagement of specific PFC subregions. The first experiment will assess the representation of memory competition in regions that process perceptual elements of events and are reactivated during retrieval. It is hypothesized that the fidelity of signals in these perceptual regions will be related to PFC engagement. The second experiment will assess the generality of PFC mechanisms that resolve competition by formally testing for overlap between mechanisms that govern competitive retrieval and those that govern perceptual decision-making. Finally, the third experiment will assess the adaptive qualities of retrieval, probing the biases in reactivation that come about as a consequence of prior acts of retrieval. Across each of these experiments, experimental paradigms will be structured such that relevant (target) and irrelevant (distracter) memories are always from visual categories that are processed by distinct perceptual cortical regions (i.e., Faces and Scenes). This approach will allow for direct comparison of reactivation that is related to targets vs. distractors and will therefore be essential for gauging the relationship between PFC engagement and the signals propagating from perceptual cortical regions. These experimental pursuits are intended to form the basis for more applied experimental questions related to the memory failures that are frequently observed in a variety of clinical and non-clinical states. Summary: The present proposal seeks to use functional MRI to better understand how, at a neural level, competition between episodic memories is experienced and resolved. This work underscores the fact that memory often fails not because information is not learned in the first place, but because retrieval operations are overwhelmed by competition. The insights to be gained are of obvious and critical relevance to memory disorders and impairments associated with aging and dementia, particularly of the Alzheimer's type.