Highlighting Faculty Member David Clewett
Date published: 01/04/23
We cannot process or remember everything we encounter. How, then, do we acquire and hold onto memories that matter? My work seeks to understand the brain mechanisms that facilitate attention and memory for highly emotional and salient events.
In my cognitive neuroscience lab, we examine how emotional and everyday arousal influence the selectivity (what we remember) and structure (how events are remembered) of human memory. We use neurophysiological, neuroimaging, and behavioral techniques to study the following topics:
(1) How the mind becomes more selective under arousal
Memories are not arbitrary records of past events – they are highly selective. Decades of research show emotionally arousing experiences, such as a car crash or celebration, are preferentially processed and remembered. However, a surge of arousal also exerts highly selective effects on memory for other contextual details. So how do we predict when emotion will enhance or impair attention and memory? Our research shows that physiological arousal – a brain state characterized by intense ‘mental activation’ – enhances processing of important information, while suppressing processing distracting information. Thus, insofar as attention functions as a spotlight, arousal seems to brighten and focus this spotlight on things that matter, leaving fewer mental resources to process things that don’t. Extending this line of work, we are now investigating how different arousal inductions influence the fate of recently acquired memories. We also use pupillometry, a biomarker of arousal states, to determine how activation of the locus coeruleus-norepinephrine system facilitates mental selectivity and energizes adaptive behavior.
(2) How emotional states shape the structure and coherence of memory
Time unfolds continuously, yet our memories are stored as discrete and meaningful episodes. This raises a fundamental yet often unasked question: how does the brain construct meaningful episodes in long-term memory? We recently found that a sudden context shift, or ‘event boundary’, elicits a burst in physiological arousal that helps to transform continuous experience into distinct and memorable events. In short, arousal is part of the punctuation of human memory. Building upon these findings, we are now examining how fluctuations in our thoughts and feelings influence neural and memory representations of time and events. Currently, we are using musical stimuli, continuous behavioral tracking, narratives, and natural language processing tools to investigate how memories take shape under emotional circumstances. We are also examining if these memory processes become altered in post-traumatic stress disorder, healthy aging, and Alzheimer’s disease.
(3) How to harness forgetting techniques to weaken unwanted memories
The strength and persistence of emotional memories is usually adaptive: we draw upon these meaningful experiences to guide how we think, feel, and behave. However, the enduring nature of emotional memories can also become harmful when aversive events spring to mind involuntarily and intrude on future thoughts or behavior. Current treatments for traumatic memories often require explicit recollection of negative experiences. But these approaches can be problematic if they also induce distress. While objective physiological and behavioral symptoms are important measures of treatment efficacy, the subjective experience of the patient is a crucial and often overlooked component of mental health treatment. We are interested in studying ways of reactivating and weakening emotional memories indirectly. Identifying such “backdoor” approaches may ultimately provide a safer method of modifying memories of trauma and everyday emotional incidents.
Bio: Dr. Clewett was born and raised in California. After receiving a B.S. in Biopsychology from UCSB, he completed his PhD in Neuroscience at the University of Southern California in 2016. He then conducted a postdoctoral fellowship with Dr. Lila Davachi at New York University and Columbia University, where he studied memory encoding and consolidation processes. Having received a sufficient dose of New York winter, he returned happily back to CA and his flip flops to start his cognitive neuroscience lab at UCLA. To learn more about his lab’s work, please visit: https://clewettlab.psych.ucla.edu