PTSD: The Brain Basis of Susceptibility

The script begins with an introduction to a webinar series hosted by the Brain, Behavior, and Research Foundation (BBRF), with Dr. Jeff Florstein, the President and CEO, welcoming attendees. The focus is on mental health research funding, with an emphasis on the BBRF's role as the world's largest private funder. The BBRF Scientific Council, comprising 194 mental health researchers, is highlighted for its role in reviewing grant applications and selecting projects with breakthrough potential. The foundation's broad support for research on various brain illnesses is underscored, with a mention of Dr. Nathaniel Harnett's upcoming presentation on PTSD and the brain basis of susceptibility.

Dr. Nathaniel Harnett presents on PTSD, exploring the brain's basis for susceptibility to the disorder. He discusses the importance of threat learning circuits, including the amygdala, hippocampus, and prefrontal cortex, in the development of PTSD. Harnett emphasizes the need to understand how trauma affects these neural circuits and how they contribute to PTSD symptoms. He also highlights the prevalence of trauma and its public health significance, noting that many individuals experience at least one traumatic event in their lifetime. The presentation aims to identify neurobiological signatures of PTSD susceptibility to improve diagnosis and treatment.

This section delves into how trauma impacts neural circuits associated with threat learning and the subsequent development of PTSD. Harnett discusses the use of neuroimaging to study the brains of individuals who have recently experienced trauma, aiming to identify specific neural processes that make some individuals more susceptible to PTSD. The importance of understanding the disruption of safety learning and the role of top-down emotional control regions is highlighted. The presentation suggests that traumatic stress affects the brain's ability to learn safety, which could be a key factor in PTSD susceptibility.

The script describes neuroimaging studies conducted in the early aftermath of trauma to understand susceptibility to PTSD. It details the process of recruiting individuals who have recently survived a traumatic event and conducting MRI studies to observe brain activity during tasks that assess threat learning. The studies aim to identify prognostic neuroimaging biomarkers that could predict the development of PTSD. The presentation discusses the findings from these studies, which show differences in neural responses between trauma survivors and non-trauma-exposed individuals, particularly in the context of safety learning.

The focus shifts to the impact of early life experiences, such as adverse childhood experiences (ACEs), on the neural circuitry related to PTSD susceptibility. The script discusses how childhood maltreatment can affect the structural integrity of white matter tracts in the brain, potentially contributing to PTSD symptoms later in life. It also explores the role of neighborhood disadvantage and access to green space, showing how these environmental factors can influence brain function and structure in trauma survivors. The presentation suggests that the wider context of development can have observable effects on how the brain responds to stress.

This section addresses the role of racial disparities in the neurobiology of PTSD susceptibility. The script presents data showing that racial and ethnically marginalized groups experience a disproportionate exposure to adverse childhood experiences and live in more disadvantaged environments. It discusses the potential impact of these disparities on the neural circuits thought to underlie PTSD susceptibility. The presentation calls for a consideration of racial inequities when developing generalizable neural targets for PTSD treatment and prevention.

The script explores the impact of racial disparities on brain development, particularly in the context of PTSD susceptibility. It discusses research findings that show significant differences in brain structure and function between black and white individuals, which are attributed to disparities in experiences such as family conflict, neighborhood disadvantage, and trauma exposure. The presentation suggests that addressing these disparities could help normalize differences in brain biology and improve our understanding of PTSD susceptibility across diverse populations.

The presentation concludes by emphasizing the need to integrate sensory circuitry, particularly visual circuitry, with threat neurocircuitry to develop more generalizable and accurate models for PTSD susceptibility. It discusses ongoing research that explores the interaction between the ventral visual stream and threat-related brain regions, suggesting that this integration may provide a more reliable and generalizable approach to understanding and predicting PTSD. The script highlights the importance of considering both sensory and threat circuitry to derive robust neural targets for PTSD susceptibility.

The final paragraph discusses the implications of racial inequity for PTSD research and treatment. It acknowledges the bias that can seep into neurobiological models of PTSD due to ongoing inequities and the structure of scientific studies. The script calls for broadening these models to include sensory circuitry and to consider pre-traumatic influences, developmental context, and the impact of racial inequity on neural responses. The presentation suggests that integrating data from various neural circuits and modalities will be key to developing generalizable markers of PTSD pathophysiology.

The script concludes with a Q&A session where the presenter, Dr. Nathaniel Harnett, addresses questions from the audience. Topics discussed include strategies for helping children exposed to trauma, the relationship between PTSD neurobiology and comorbid diagnoses, and the potential role of transcranial magnetic stimulation (TMS) as a treatment for PTSD. The presentation ends with a call to action for donations to support the Brain, Behavior, and Research Foundation's research efforts, emphasizing the importance of collaborative work in improving the lives of those living with mental illness.