The information-rich and constantly changing environment that we interact with poses a great challenge to our memory: we cannot process and remember exactly everything we experience. The quality and quantity of remembered information subsequently set the upper limit for various cognitive processes, such as decision making, language comprehension, and intelligence. Xie’s research program seeks to understand how the human brain addresses this challenge by investigating the neurocognitive mechanisms underlying memory formation, retention, and retrieval.
In this talk, Xie will explore how the brain retains precise item-specific memory content, and how it may scale up to efficiently remember a large amount of associative information. First, Xie will present converging evidence from fMRI, intracranial EEG, brain stimulation, and lesion case studies to test the hypothesis that precise item-specific memory content is supported by a medial temporal lobe mechanism that is shared across long-term memory (LTM) and working memory (WM). Specifically, pattern separation computation within the medial temporal lobe, a well-established mechanism underlying LTM fidelity, can tease apart similar information to ensure the encoding and retention of precise individual WM content. Next, moving beyond item-specific information, Xie will explore how complex associative information can be efficiently remembered and retrieved. Xie will present evidence from laboratory, online crowd-sourced, computational modeling, and intracranial EEG methods to show that the brain leverages acquired structural knowledge of associative verbal content in the anterior temporal lobe to support successful reactivation of associative information during memory retrieval. Finally, given the dynamic and potentially shared neural processes underlying WM and LTM, Xie will discuss a framework for investigating how information is transmitted across different activation states in WM and LTM. This framework may help us understand open questions about the structure of memory, memory deficits in aging and psychopathology, and the role of WM-LTM interaction in complex mental functions such as memory-based decision and fluid intelligence.