Jennifer Blackford - US grants

DESCRIPTION (provided by applicant): This is an application for a Mentored Research Scientist Development Award with a focus on developing expertise in neuroimaging and genetics methods to study temperamental vulnerabilities for psychiatric disease. Inhibited temperament is the predisposition to respond to new people, places or things with fear and avoidance. This heritable, evolutionarily-conserved, and well-established phenotype is a risk factor for social anxiety disorder (SAD) and depression. Recent studies have provided preliminary evidence for genetic risk factors and neural vulnerabilities for inhibited temperament, but a comprehensive, integrated view is still needed. A study with multiple levels of measurement in a single cohort will provide the necessary information to develop models of the genotype-phenotype relationships in inhibited temperament to further our understanding of the mechanisms which increase risk. Research Plan: The candidate proposes to conduct a study of genetic, neural and emotional factors in inhibited temperament. An extreme discordant phenotype method will be used, resulting in two divergent temperament groups. Genetic risk factors will be measured by allelic variation associated with genes involved in monoaminergic neurotransmitter and stress hormone systems. Brain function in the amygdala and related paralimbic areas will be assessed using both activation and temporal dynamics with an event-related fMRI novelty paradigm. Mood, personality, anxiety and depression will be measured. Between-group tests for differences in genetic, neural and emotional variables will be complemented with analytic model testing of interrelationships between genetic, neural and emotional factors. Career Development Plan: Training at Vanderbilt University will emphasize skills necessary for neuroimaging and genetics and will include: neuroimaging methods and analysis, temporal dynamics analysis, neuroanatomy and physiology, genetic approaches to complex traits, and statistical genetics. Experts in the fields of anxiety/mood disorders, temperament, imaging, psychiatric genetics and statistical genetics will provide mentorship and consultation. This program of training and research experience will provide the candidate with the necessary depth and breadth of knowledge to become an independent affective neuroscientist focused on the identification, quantification and elaboration of how temperament increases risk for psychiatric disease. PUBLIC HEALTH RELEVANCE: SAD is a common psychiatric disease affecting 15 million people and is often comorbid with other anxiety disorders, mood disorders, and alcohol use disorders. SAD can be a serious and debilitating disease with impact on daily functioning and reduced quality of life. Understanding how inhibited temperament increases risk for SAD will provide new information for developing methods for identification, novel interventions, and primary prevention strategies for psychiatric disease in children and adolescents with these temperamental vulnerabilities.

? DESCRIPTION (provided by applicant): Post-traumatic stress disorder (PTSD) is a disabling and prevalent disorder that is rapidly becoming the most common mental health problem facing Veterans returning home from Iraq and Afghanistan. In addition to the devastating effects of PTSD, secondary effects include increased risk for suicide, depression, and substance use disorders. Unfortunately, PTSD is often resistant to current therapeutic interventions and a full recovery is uncommon. The development of therapies targeted at the underlying pathophysiology is a promising avenue for the effective treatment of PTSD, but to develop these treatments, first we must better understand the underlying neurobiological mechanisms. To date, most research on the neurobiological mechanisms of PTSD has focused on an amygdala-mediated fear circuit. Compelling animal models show that a different neural circuit, mediated by the bed nucleus of the stria terminalis (BNST), is critical for anxiety. The BNST also mediates hypervigilance and responses to stress, which may explain the critical features of PTSD. Thus, we propose that combat Veterans with PTSD have alterations in a BNST-mediated anxiety circuit. We have recently characterized the BNST neural circuitry in humans and have developed novel methods to examine BNST function. Our preliminary data demonstrates that the BNST is specifically engaged in situations where a threat is unpredictable, and that individuals with PTSD show significantly heightened BNST responses to unpredictable threat relative to predictable threat. The study will focus on three specific aims: (1) Investigate BSNT function in individuals with PTSD to determine if PTSD is associated with heightened BNST responses to unpredictable threat (2) Identify patterns of PTSD-related functional dysconnectivity in the BNST-mediated anxiety circuit. A circuit-level approach is critical for identifying interactions between regions in the circuit. (3) Test for relationships between units o analysis in the RDoC Negative Valence System/Response to Potential Harm. A dimensional approach that is consistent with NIMH's RDoC objectives is employed in this project by examining a novel neurobiological mechanism of PTSD across multiple units of analysis, from neural circuit to behavior. This project will also elucidate the brain-physiology-symptom relationships within two constructs of the Negative Valence system: Response to Potential Harm (unpredictable threat, BNST) and Response to Acute Threat (predictable threat, amygdala). Ultimately we aim to elucidate the neurobiological mechanisms underlying PTSD to identify novel brain targets for treatment. Importantly, the BNST and amygdala respond differently to pharmacological agents; therefore, if we find evidence for BNST alteration in PTSD, the BNST and responses to unpredictable threat will provide novel targets for treatment.

Alcohol use disorders (AUDs) are disabling and prevalent conditions that affect almost one-third of Americans. In addition to the devastating effects of AUDs, secondary effects include increased risk for suicide, depression, and substance use disorders. While initial treatments exist, unfortunately, relapse is common, making long- term recovery difficult. Given the high rates of relapse, interventions that seek to prevent relapse have high potential impact. Animal models of addiction have substantially informed our understanding of the stages of addiction? binge/intoxication, withdrawal/negative affect, and preoccupation/anticipation?and their underlying pathophysiology. Chronic alcohol exposure causes neuroadaptive brain changes in an attempt to maintain homeostasis. During early abstinence, hyperactive stress systems result in negative affect, anxiety, and depression which are thought to lead to relapse through negative reinforcement. An emerging theme from animal models is the involvement of the extended amygdala, including the bed nucleus of the stria terminalis (BNST), in withdrawal and reinstatement. While animal models of addiction are heavily studied under the assumption of their utility in translation to humans, the role of the BNST in human alcohol abstinence remains unknown. A major barrier to this work has been technological limitations in neuroimaging of the BNST because of its small size. We have recently overcome this challenge and have characterized the BNST neural circuitry in humans and have developed novel methods to examine BNST function. Our published findings show vast consistencies in BNST circuitry across species, providing a necessary foundation for translational studies. Our pilot studies show that the BNST is specifically engaged in mildly stressful situations where an upcoming threat is unpredictable. To investigate the role of the BNST in human addiction, we will study adults with moderate- severe AUDs who have been abstinent for one month, a critical time for relapse. The study will focus on three specific aims: (1) Determine whether there are intrinsic differences in BNST function and BNST circuit connectivity during early abstinence; (2) Determine whether there are task-based differences in BNST function and BNST circuit connectivity during early abstinence; (3) Determine the relationship between BNST function/connectivity, stress response (cortisol and skin conductance), and anxiety/depression symptoms in early abstinence. Based on findings from animal models, we predict that during early abstinence, the BNST will show hyperactivity and altered connectivity both ?at-rest? (intrinsic) and in response to a mildly stressful task. Furthermore, we predict that variation in stress response will mediate the relationship between BNST function/connectivity and anxiety and mood symptoms. The successful completion of this study will fill a critical knowledge gap, assessing the predictive validity of animal models championed by much of the neurobiology community that have heavily implicated the extended amygdala and BNST in alcohol use disorders. Elucidating these neural mechanisms is a crucial step in identifying novel targets for the prevention and treatment of alcohol use disorders.

Project Summary Anxiety disorders (ADs) are the most prevalent psychiatric ailments in children and adolescents. Childhood ADs substantially impair development and confer high risk for later psychopathology including persistent anxiety, depression and comorbid substance abuse. Given the high prevalence and long-term negative impact of childhood ADs, it is critical to successfully treat ADs early in development. Unfortunately, many children with these disorders either fail to fully respond to treatment or relapse. Understanding the biology of childhood ADs is crucial for developing early interventions with the potential to reduce the chronicity and comorbidity associated childhood onset. Cross-species conservation of brain-behavior relationships provides a unique opportunity to link basic neuroscience in nonhuman primates with clinical neuroscience in childhood ADs to identify the neural substrates of childhood anxiety. The proposed project will capitalize on this exceptional advantage by using two integrated approaches: 1) a multisite multimodal imaging study that extends promising basic science findings in nonhuman primates to a large sample of preadolescents with ADs and 2) a molecular study that translates neural findings in childhood ADs to gene expression studies in nonhuman primates using our fully-phenotyped nonhuman primate brain bank focused on alterations in neuroplasticity transcripts. Findings from our nonhuman primate studies highlight the importance of identifying neural substrates that contribute to shared variance across ADs, as well as specific neural substrates that are associated with particular anxiety phenotypes. This approach is consistent with evidence of shared and specific features of childhood ADs: most children with ADs present with an admixture of symptoms and treatment responses are similar across diagnoses suggesting shared neural substrates; however, substantial variation in symptoms and presentation suggest heterogeneous neural substrates. The study will focus on three specific aims: (1) Identify neural alterations that are shared among childhood generalized anxiety disorder, social anxiety disorder, and separation anxiety disorder; (2) determine neural alterations linked to specific anxiety-relevant RDoC constructs (i.e. acute, potential, and sustained threat, and generalization of conditioned fear); and (3) Investigate molecular alterations in brain regions central to childhood ADs, guided by the childhood AD studies in Aims 1 and 2, with a particular focus on neuroplasticity-related alterations. Studying a large sample of AD children is critical to parse the heterogeneity common in childhood ADs; to achieve this goal, we have assembled three sites with expertise in anxiety (nonhuman primate models of anxiety, childhood anxiety, developmental psychology) and advanced methods (gene expression, neuroimaging, and statistics). Ultimately we aim to elucidate the neurobiological mechanisms underlying childhood ADs to identify novel brain targets for treatment, including shared and phenotype-specific neural correlates of childhood ADs.

Schizophrenia is a severe and heterogeneous mental disorder that impacts most domains of function including behavior, cognition, and emotion. Recent models have highlighted important alterations of the emotion brain networks in schizophrenia that contribute to schizophrenia symptoms, like paranoia and delusions. To date, the studies of emotion in schizophrenia have primarily focused on fear processing and have shown heightened amygdala responses to neutral stimuli and altered amygdala-prefrontal cortex connectivity. However, recent research suggests that another brain region?the bed nucleus of the stria terminalis (BNST)?may play a critical role in anxiety and that BNST-mediated anxiety is distinct from amygdala-mediated fear. The RDoC?s Negative Valence System recognizes this fear-anxiety distinction and has separate constructs for Response to Acute Threat (amygdala) and Response to Potential Harm (BNST). To our knowledge, the BNST has yet to be examined in individuals with schizophrenia. Using methods pioneered by our lab to study the human BNST, we have collected preliminary data in schizophrenia. Our pilot data provides initial evidence for BNST connectivity differences in both response to unpredictable threat, a measure of the response to potential harm construct, and during a resting state in individuals with schizophrenia compared to healthy controls. Further, we found evidence that BNST alterations in schizophrenia differ for those who do or do not have comorbid anxiety. Individuals with schizophrenia and anxiety disorders demonstrated stronger connectivity between BNST and multiple brain regions involved in threat detection, uncertainty, and anxiety relative to those with schizophrenia and no anxiety disorder. The current study will investigate BNST connectivity in three groups: individuals with schizophrenia with a comorbid anxiety disorder (SZ+ANX), individuals with schizophrenia without a comorbid anxiety disorder (SZ-ANX), and healthy controls (HC). We hypothesize that individuals with schizophrenia will have altered BNST connectivity in response to unpredictable threat and altered BNST intrinsic connectivity relative to HC. In addition we predict that SZ+ANX group will show BNST hyperconnectivity relative to SZ- ANX. We will test these hypotheses with three specific aims. (1) Investigate BNST connectivity in response to unpredictable threat in individuals with schizophrenia; (2) Determine whether there are differences in BNST intrinsic connectivity in individuals with schizophrenia; (3) Test for relationships among BNST connectivity, stress responses (skin conductance and cortisol), and clinical symptoms in schizophrenia. Given the prevalence of anxiety in schizophrenia, BNST alterations within schizophrenia are likely and may shed new light on the neurobiological mechanisms underlying emotion alterations in schizophrenia. The results from the proposed study can provide a foundation for future studies of emotion in schizophrenia, determine whether there are neurobiological differences in anxiety subgroups, and guide the development of novel neuroscientifically-informed treatments.