The nature of item representations in memory.

我们研究的首要目标是了解记忆的本质和支持不同类型记忆表征形成和检索的神经系统。本研究的重点是研究项目记忆表征的本质。这项工作的目的是利用神经成像和眼动监测来揭示记忆中不同类型的物品表征的存在，并了解支持有意识识别物品的潜在神经和行为机制。我们将研究不同区域的神经重复抑制效应、眼动重复效应和不同条件下的意识识别之间的关系，为多种类型的项目表征提供证据。我们预测有互补的神经系统（海马体和皮质区域）支持项目表征的形成。然而，这些表征的性质，以及它们支持意识识别的方式，将有所不同。我们提出，由皮层（包括周围皮层）介导的表征将是不灵活和高度特异性的，因此对先前看过的物品所做的任何改变（例如，观点，特征改变）都会导致感知加工的变化和有意识识别的下降。相比之下，海马体会通过整合相关信息来调节灵活的项目表征，即使在项目发生变化时，这也可以用来支持有意识的识别。除了提供由不同的神经系统介导的灵活和特定的项目表征的证据外，这项工作还将神经重复抑制效应与行为联系起来，并解决文献中关于眼动重复效应背后的神经系统的争论。最后，我们将揭示我们对单个项目的记忆是不灵活不变的，还是不断变化并受到与之相关的信息的影响。后一项发现表明，“感知”和“记忆”并没有被清晰地描绘出来，但这些认知过程相互影响。

The overarching goal of our research is to understand the nature of memory and the neural systems that support the formation and retrieval of different classes of memory representations. The focus of this proposed research is on the nature of item memory representations. The objectives of this work are to use neuroimaging and eye movement monitoring to reveal the existence of distinct types of item representations in memory and to understand the underlying neural and behavioral mechanisms that support conscious recognition of items. We will examine the relationship between neural repetition suppression effects in distinct regions, eye movement repetition effects and conscious recognition under a variety of conditions to provide evidence for multiple types of item representations. We predict that there are complementary neural systems (hippocampus versus cortical regions) that support the formation of item representations. However, the nature of those representations, and the manner by which they support conscious recognition, would differ. We propose that representations mediated by the cortex, including the perirhinal cortex, would be inflexible and hyperspecific, such that any change made to a previously viewed item (e.g., viewpoint, feature change) would cause a change in perceptual processing and a decline in conscious recognition. By contrast, the hippocampus would mediate flexible item representations through the integration of associated information, which could be used to support conscious recognition even when the item has undergone a change. In addition to providing evidence that there are flexible, as well as specific, item representations mediated by distinct neural systems, this work will relate neural repetition suppression effects to behavior, and resolve debates in the literature regarding the neural systems that underlie eye movement repetition effects. Finally, we will reveal whether our memories for single items are inflexible and unchanging, or constantly in flux and influenced by the information that has come to be associated with them over time. The latter finding would suggest that 'perception' and 'memory' are not clearly delineated, but that these cognitive processes influence each other.