Research

FOCUS:

Memory updating & stress

Memories are stored in the brain as cellular ensembles activated during learning and then reactivated during retrieval. But our memories are not perfect snapshots of the past, they are constantly evolving. They are networks of activity that interact with the world around us.

My lab is specifically interested in how memories change, and how they are updated when new information is presented. Memory malleability, and the ability to incorporate new information and update environmental representations accordingly is a critical component of behavioral flexibility in learning and memory. Memory updating occurs through retrieval-induced plasticity and although it is an adaptive mechanism in an ever-changing environment, we often see decreased flexibility in stress-related disorders. It is not surprising that stress can have such a negative impact on brain health.

We are interested in the neuromodulatory inputs that govern how memories change, and how these changes manifest at the cellular and ensemble level. To that end, we are investigating the involvement of noradrenergic and dopaminergic projections to the hippocampus in assigning new networks to mediate encoding that reflects environmental change. Stress can induce dysregulation of these arousal systems contributing to maladaptive memory processes and behavioral states. A principal hypothesis forming the primary basis of our research is that stress-induced impairments in neural mechanisms such as memory updating, where memory systems are fixed rather than flexible, specifically contribute to symptoms observed in anxiety disorders such as PTSD (e.g., rumination). The persistence of maladaptive memories also contributes to drug addiction. Therefore, we are also interested in the stability and flexibility of drug-related memories.

Strategy:

Alleviating Maladaptive States Through Memory Modulation

Our goal is to identify target circuits involved in psychiatric disease-related states. Our experiments involve characterizing hippocampal ensemble dynamics and catecholaminergic signatures across stages of learning using mouse models that incorporate appetitive and aversive stimuli. We employ a variety of approaches including behavior, pharmacology, molecular biology, viral based in vivo circuit manipulations (e.g., optogenetics, chemogenetics) and imaging using genetically encoded indicators.

Additionally, we aim to target memory circuits with novel modulation strategies that mechanistically probe how maladaptive memories can be “reset” to ultimately alleviate dysregulated signaling, reverse maladaptive behavioral states, and re-establish cognitive and behavioral flexibility compromised in these models.

Questions:

To what degree does stress affect the stability and flexibility of memory traces and how does this contribute to maladaptive cognition and behavior?

In the therapeutic context of stress and anxiety-related disorders and drug addiction, can we find ways to ‘reset’ memory systems to mitigate dysregulated signalling?

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Upcoming Events

Apr 20, 2024

Undergraduate Research Engagement Symposium, Loyola University Chicago, Chicago, IL

Memory-Updating Impairments in Anxiety Disorders: Individual Differences and Sex Differences in the Vulnerability to Post-Traumatic Stress Disorder

Genetically Labeling and Optically Manipulating Cocaine-Related Hippocampal Engrams to Restore Cognitive and Behavioral Flexibility

Apr 18, 2024

Midwestern Psychological Association Meeting Psi Chi, Chicago, IL

Fear memory engrams in the dorsal hippocampus during fear learning and fear generalization: Implications for post-traumatic stress disorder

feb 26, 2024

Wilfrid Laurier University, Behavioural Neuroscience Seminar Series, Waterloo, ON, CAN

Manipulating fear and drug-related hippocampal engrams to promote cognitive and behavioral flexibility

feb 13, 2024

Loyola University Chicago (Maywood), Neuroscience Seminar Series, Chicago, IL

Manipulating fear and drug-related hippocampal engrams to promote cognitive and behavioral flexibility

Feb 3, 2024

Loyola University Chicago (Lakeshore), Chicago Brain Bee, Chicago, IL

How memories are involved in addiction and PTSD: Sonia Arora and Lola Papanikolaou

jan 30, 2024

Loyola University Chicago (Lakeshore), Neuroscience Seminar Series, Chicago, IL

Manipulating fear and drug-related hippocampal engrams to promote cognitive and behavioral flexibility

Society for Neuroscience Meeting, Washington, DC

The role of cocaine and extinction-associated engrams in driving / preventing drug-seeking behavior using conditioned place preference

Locus coeruleus modulation of hippocampal fear memory traces: hippocampal flexibility and context generalization

Does reactivation of hippocampal drug-related engrams serve as a re-experiencing effect of the drug-related state including locomotor sensitization effects?