Dr. Bridget Callaghan's Research at UCLA: Exploring the Interplay of Early Life Experiences, the Microbiome, and Mental Health

Introduction

Dr. Bridget Callaghan is an Assistant Professor in the Department of Psychology at the University of California, Los Angeles (UCLA). Her research focuses on the intricate relationship between early life experiences and their lasting impact on both mental and physical well-being. Dr. Callaghan's work, conducted in her Brain and Body Lab (BaBLab) at UCLA, employs a multi-faceted approach to unravel the complex mechanisms through which early adversity shapes our health across the lifespan.

Academic and Professional Background

Dr. Callaghan's academic journey began at the University of New South Wales, Australia, where she earned a bachelor’s degree in Psychology, followed by a master’s degree in Clinical Psychology and a doctorate in Psychology. Her commitment to understanding the intricate links between the brain, body, and behavior led her to pursue postdoctoral training in neuroimaging and child development at Columbia University and New York State Psychiatric Institute. This training was supported by prestigious fellowships, including a National Health and Medical Research Council postdoctoral training grant from Australia, a Brain and Behavior Research Foundation Young Investigator grant, and a career development award (K99) from the National Institutes of Mental Health.

Before joining UCLA, Dr. Callaghan gained experience working with animal models of early adversity, as well as in behavioral, fMRI, and biological research within human populations. She also worked clinically in the field of developmental psychology.

The Brain and Body Lab (BaBLab) at UCLA

At UCLA, Dr. Callaghan directs the Brain & Body Lab in the Department of Psychology. The BaBLab provides a platform for interdisciplinary research, bringing together expertise in psychology, neuroscience, and microbiology to investigate how early life experiences "get under the skin" to influence mental and physical health. The lab opened in 2019.

Her lab takes a multi-faceted approach toward examining the effects of early-life adversity, including studying behaviors related to emotion and memory development, observing activation of underlying neural systems using fMRI, characterizing the gut microbiome using gene sequencing, evaluating basic physiological health (using e.g., gastric function, heart rate, skin conductance), and exploring the role of parental scaffolding in healthy emotional development.

Research Focus: Early Life Adversity and its Long-Term Consequences

Dr. Callaghan's research is centered on understanding how early life experiences, particularly adversity, can shape the development of both the brain and the body, ultimately influencing an individual's susceptibility to mental and physical health problems. Early life experiences are known to shape both physical and mental health, however, the precise mechanisms by which such shaping occurs have yet to be established. Her work spans from animal models to human studies, allowing her to explore these mechanisms at multiple levels of analysis.

As both a clinically-trained psychologist and a basic science researcher, Dr. Callaghan performs interdisciplinary research linking physical and emotional health in children who experience extreme psychosocial deprivation due to institutionalized care, children who have experienced out of home (e.g., foster care) placements within the United States, and youth who have experienced physical illnesses in early life.

Key Research Areas

The Microbiome-Gut-Brain Axis

One of Dr. Callaghan's primary research interests lies in the role of the microbiome-gut-brain axis in mediating the effects of early adversity on mental health. She heads the Mental Disorders and Pain research theme at the Goodman Luskin Microbiome Center, where she investigates the complex interactions between the gut microbiome, the brain, and behavior.

Dr. Callaghan was awarded $3,891,851 from the National Institute of Mental Health (NIMH) to study the microbiota-gut-brain axis pathways associated with depression and anxiety in adversity-exposed adolescents. This grant builds upon Callaghan’s previous research, which found that children and adolescents who experienced adversity had changes in their microbiome. She is going one step further, honing in on what specific bacteria species and strains are linked to adversity, and studying how these changes interplay with the brain reward pathway and puts youth at risk of anxiety and depression.

Neural Circuits and Emotional Development

Dr. Callaghan's research also explores the impact of early adversity on the development of neural circuits involved in emotion regulation and memory. Using fMRI, she investigates how early experiences can alter the structure and function of brain regions such as the amygdala, which plays a crucial role in processing emotions like fear and anxiety.

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Cross-Species Analysis of Parental Effects

Dr. Callaghan's work extends to cross-species analyses of parental effects on emotion circuitry development. By studying both human and animal models, she aims to identify conserved mechanisms through which early caregiving experiences shape the developing brain.

Intergenerational Transmission of Adversity

Dr. Callaghan's research has also shed light on the potential for the intergenerational transmission of the effects of early adversity. Her studies in rodent models have shown that the dysregulation of emotion caused by early-life trauma can be passed down to subsequent generations.

Selected Publications

Dr. Callaghan's research has been published in numerous high-ranking journals in the fields of psychology, neuroscience, and developmental biology. Some notable publications include:

Callaghan, BL, Tottenham, N. The stress acceleration hypothesis: Effects of early-life adversity on emotion circuits and behavior. Current opinion in behavioral sciences 7, 76-81, 2016.
Callaghan, BL, Tottenham, N. The neuro-environmental loop of plasticity: A cross-species analysis of parental effects on emotion circuitry development following typical and adverse caregiving. Neuropsychopharmacology 41 (1), 163-176, 2016.
Callaghan, BL, Richardson, R. Maternal separation results in early emergence of adult-like fear and extinction learning in infant rats. Behavioral neuroscience 125 (1), 20, 2011.
Cowan, CSM, Callaghan, BL, Kan, JM, Richardson, R. The lasting impact of early‐life adversity on individuals and their descendants: Potential mechanisms and hope for intervention. Genes, Brain and Behavior 15 (1), 155-168, 2016.
Callaghan, BL, Richardson, R. The effect of adverse rearing environments on persistent memories in young rats: removing the brakes on infant fear memories. Translational psychiatry 2 (7), e138-e138, 2012.
Callaghan, BL, Sullivan, RM, Howell, B, Tottenham, N. The international society for developmental psychobiology Sackler symposium: Early adversity and the maturation of emotion circuits-A cross‐species analysis. Developmental psychobiology 56 (8), 1635-1650, 2014.
Callaghan, BL, Fields, A, Gee, DG, Gabard-Durnam, L, Caldera, C, et al. Mind and gut: Associations between mood and gastrointestinal distress in children exposed to adversity. Development and Psychopathology 32 (1), 309-328, 2020.
Callaghan, BL, Gee, DG, Gabard-Durnam, L, Telzer, EH, Humphreys, KL, et al. Decreased amygdala reactivity to parent cues protects against anxiety following early adversity: An examination across 3 years. Biological Psychiatry: Cognitive Neuroscience and Neuroimaging 4 (7), 664-671, 2019.
Chu, KA, Schwartz, C, Towner, E, Kasparian, NA, Callaghan, B. Parenting under pressure: A mixed-methods investigation of the impact of COVID-19 on family life. Journal of Affective Disorders Reports 5, 100161, 2021.

Awards and Recognition

Dr. Callaghan's contributions to the field have been recognized with numerous awards, including:

K-99 Pathway to Independence Award from the National Institute for Mental Health
Kucharski Young Investigator Award from the International Society for Developmental Psychobiology
Young Investigator Grant from the Brain Behavioral Research Foundation

Potential Therapeutic Implications

Dr. Callaghan's research has important implications for the development of novel therapeutic interventions for individuals who have experienced early adversity. For example, her work on the microbiome-gut-brain axis suggests that targeting the gut microbiome with probiotics or specialized diets could potentially improve mental health outcomes in adversity-exposed individuals.

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Callaghan believes that potential noninvasive treatments would be probiotics or specialized diets that help to nourish and feed the bugs identified in these pathways. She also stated that she doesn't think this is going to replace traditional therapies for mental health, but she does think there's an important role for nourishing our bugs in ways that support mental health.

Current Research Initiatives

Currently, Dr. Callaghan is enrolling 300 adolescents ages 12-15 years old in a five-year study. The study population consists of children who have experienced or are currently experiencing adversity, as defined by their exposure to maltreatment. This study will further explore the pathways by which adversity impacts the microbiome, brain, and mental health, with the goal of identifying new targets for prevention and intervention.

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