Remembering amidst competition: neural systems for reactivation and selection

描述(申请人提供)：有效的情节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，而不是无关的记忆。虽然前额叶皮质(PFC)被认为在竞争记忆中起着选择的关键作用，但关于竞争是如何在神经水平上表现出来的，以及PFC如何与后脑皮质部位相互作用来实现选择，仍然存在相当大的模糊性。这项建议旨在促进对竞争如何影响支持记忆重新激活的大脑皮层区域的处理，以及来自这些区域的信号如何与特定PFC亚区的参与有关的理解。第一个实验将评估记忆竞争在处理事件知觉元素的区域中的表征，并在提取过程中重新激活。假设这些知觉区域中信号的保真度将与PFC参与有关。第二个实验将通过正式测试管理竞争性检索的机制和管理知觉决策的机制之间的重叠来评估解决竞争的PFC机制的一般性。最后，第三个实验将评估提取的适应性，探索由于先前提取行为而导致的重新激活的偏向。在每一个实验中，实验范式的结构将使相关(目标)和无关(分心)记忆总是来自视觉类别，这些类别由不同的知觉皮质区域(即，人脸和场景)处理。这种方法将允许直接比较与目标和干扰物相关的重新激活，因此对于测量PFC参与和从知觉皮质区域传播的信号之间的关系至关重要。这些实验目的是为了形成更多应用实验问题的基础，这些问题与在各种临床和非临床状态下经常观察到的记忆衰竭有关。摘要：目前的建议试图使用功能磁共振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。这项研究强调了这样一个事实：记忆经常失败，不是因为信息一开始就没有被学习到，而是因为检索操作被竞争压垮了。将获得的见解与与衰老和痴呆症，特别是阿尔茨海默氏症相关的记忆障碍和损伤具有明显和关键的相关性。

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.