Ph.D., Yale University, 1999
General Area of Research
Behavioral and cognitive neuroscientific investigations of memory encoding, consolidation and retrieval
How do we form lasting memories of our everyday experiences?
In the lab, we want to understand how experiences are initially encoded, undergo further consolidation and are later retrieved. We use behavioral and neural (conventional and high-resolution fMRI, iEEG, MEG) measures to help us learn more about the cognitive and neural operations that contribute to episodic memory.
How are memories formed? We have focused on understanding how the brain and, in particular, the medial temporal lobe (MTL) encodes our experiences. Our main approach has been to examine brain activation in MTL substructures during an experience and to identify patterns of activation that are associated with successful memory formation. We are particularly interested in how we build memories that allow us to later reconstruct the episodic details (the what, when and where) of the past.
Recently, we have also focused on understanding how our perception of event structure (i.e. segmentation) modulates both how those events become organized in memory and the neural processes used to bind information within and across events. Perception, attention, working memory and prediction all interact with encoding processes to determine what will be remembered and how it will be linked with other aspects of our ongoing experience.
Memory consolidation refers to post-encoding brain activity that strengthens the representation of an encoding event. We have focused specifically on looking for reactivation, or replay, or prior encoding events during post-encoding rest periods. While sleep has been linked with memory consolidation and memory integration, we are interested in whether some aspects of our daily experience will be replayed while we are awake! Wouldn’t that be efficient? We are also interested in the role of conscious reactivation (or retrieval) after a period of consolidation and how this can improve subsequent consolidation.
Prevailing theories of episodic memory propose that retrieval is supported by recreating the patterns of activity in the brain that were there during the original experience. It has been proposed that reactivation of cortical regions involved in the original encoding is mediated by hippocampal pattern completion triggered by the memory cue. Recent work in the lab has examined the ways in which encoding processes and retrieval goals may modulate this reactivation.