Linking temporal context reinstatement to temporal memory interference

About This Grant

Project Summary/Abstract The ability to remember when events occurred in time is not only a defining feature of episodic memory, but it is an essential feature for adaptively using memory to guide behavior. However, temporal memory is particularly prone to interference due to the fact that many of the people, locations, objects, and actions that feature in our memories tend to repeat or re-occur across time. For example, remembering when you last took a medication is complicated by interference from other memories of taking that same medication at other points in time. Thus, understanding how temporal memories are protected against interference represents an important question that is fundamental to theories of memory. Moreover, it is a topic that is highly relevant to real-world forgetting—particularly because susceptibility to temporal memory interference is often exacerbated with aging and neurodegenerative disease. Despite the importance of temporal memory, the mechanisms that protect against temporal memory interference remain poorly understood. Leading computational models of memory argue that when a stimulus re-occurs (e.g., re-watching a movie) this triggers a reinstatement of the ‘temporal context’ in which it previously occurred. In the proposed research, we will develop novel fMRI methods to measure temporal context reinstatement and to test how/whether temporal context reinstatement influences temporal memory. We will consider not only whether reinstatement influences memory for when events previously occurred, but also whether reinstatement influences temporal memory for ongoing events. Additionally, we will characterize temporal memory not only in terms of the accuracy of temporal memory estimates (the degree of error), but also potential biases in temporal memory estimates (the tendency to remember events as closer or farther apart than they actually were). Finally, motivated by recent work from human and rodent studies implicating medial temporal lobe regions in temporal processing and temporal memory, we will use high-resolution imaging to establish how subregions of the medial temporal lobe—including hippocampal subfields—contribute to temporal context reinstatement and protect against temporal memory interference. The expected outcomes of the proposed research are (1) innovative new fMRI methods for measuring temporal context reinstatement, (2) an understanding of the extent to which temporal context reinstatement influences/protects temporal memories, and (3) new insight into how subregions of the medial temporal lobe system contribute to temporal context reinstatement and temporal memory.