POST PROJECT
Team Members
Alisa Huskey, project mgr
Janey Dike, GRA
Alex Faunce, GRA
Mike Lewis, GRA
Cassie Van Orden, URA
Tanmaya Rodda, URA
Abigail Greenway, URA
Gunnar Budzyn, URA
Kameron Simmons, URA
Collaborators
Dr. Russell Jones, Psychology Dept, Virginia Tech
Dr. Mike Hughes, Sociology Dept, Virginia Tech
Dr. Tina Savla, Human Development Dept, Virginia Tech
Dr. Kye Kim, M.D., Carillion Clinic
Dr. Andrew Smith, Neuropsychology Dept, Univ of Utah
The POST group is a Mind-Body Lab collaboration with the Stress and Coping Lab (Dr. Russell Jones), which aims to examine maladaptive learning patterns associated with post-trauma psychopathology using Pavlovian Fear-Conditioning (PFC) paradigms. Fear conditioning indexes the learning process through which aversive properties of a naturally harmful stimulus come to be paired with the sensory properties of an otherwise neutral or pleasant stimulus, as well as the process through which these associations are inhibited or extinguished. Fear-potentiated startle (FPS) magnitude is the main outcome variable by which learning patterns will be determined. Level of stress exposure has been demonstrated as a modulator of fear-potentiated startle (FPS) in animal-model PFC paradigms; therefore, FPS within PFC paradigms may allow us to further elucidate the continuum between fear and anxiety.
The current project examines latent profiles of safety-signal and fear-extinction learning pattern, using a discriminant-conditioning protocol that includes safety-signal trials (i.e. no aversive stimulus) presented alternately with danger trials (i.e. aversive stimulus). Given that individuals' response over time (i.e. across extinction trials) are often non-normally distributed, growth models will examine change in FPS magnitude across trials. Specifically, Latent learning profiles will be linked with a range of clinical difficulties indexed by neuro-cognitive assessments and self-report measures of psychopathology. Individual differences in defense responding, both diagnostically and in controlled laboratory settings, implicate neurological changes distinguishing between chronically, versus acutely, threatening contexts.
Participate:
Understanding of the neurophysiological concomitants of psychological dysfunction resulting from chronic stress and trauma is crucial in the development of innovative treatments. However, researchers have struggled to find meaningful connections between neurophysiological activity and nosologically defined psychological disorders. Thus, the National Institute of Mental Health (NIMH) created the Research Domain Criteria (RDoC), which encourages novel conceptualizations of connections between physiological and behavioral dysfunction.
Chronic dysregulation of physiological inhibition leads to a heightened perception of threat, which includes the many individuals experiencing anxiety symptoms without recalling any precipitating stressful or traumatic event. The Generalized Unsafety Theory of Stress proposes that perceptual and physiological markers of generalized stress contribute to impaired learning of safe cues in chronically stressful environments.
Pavlovian threat-conditioning provides an apt paradigm for examining differences in learning during safe cues in threatening contexts. Learning to inhibit defense responses during safe contexts is the proposed mechanism of dysregulation leading to a generalized perception of unsafety.
A measure of learned fear inhibition will be used as an index of generalized unsafety. The model suggests that defense responses to actual stressors become generalized to stressor-related contexts and, eventually, all contexts. To determine differential effects of the generalized defense responding on GU, skin-conductance responses to the stressor, stressor-related contexts and generalized contexts will be examined as predictors of fear inhibition.
Additionally, indices of threat and safety learning, neurovisceral regulation, neuroendocrine reactivity and recovery and self-reported trait worry and stress symptoms will be examined as covariates of learning outcomes. With an individual-differences approach, mechanisms of stress response adaptivity may provide a functional link between descriptively-separate disorders.