Research & Publications
I'm interested in the field of affective neuroscience, the study of neural mechanisms of emotions and emotional disorders. My goal is to conduct research which will allow us to better understand the complex interactions between human behavior, emotions and our brain structure and function. Specifically, I wish to focus on stress- and anxiety-related disorders, having a personal motivation to improve treatments for individuals suffering from these debilitating disorders.
Extensive Research Description
Neurobiological processes that take place during the year that follows a traumatic event critically determine who will develop post-traumatic stress disorder (PTSD) and who will not. Among survivors of single traumatic incidents, the chronic disorder frequently follows a failure to recover from early PTSD symptoms. Longitudinal studies further describe diverging early symptom trajectories of non-remission, rapid remission, and delayed remission from early post-traumatic normative responses. To better understand the underlying neurobiology, these observable symptom trajectories must be linked with cognitive deficits and pertinent brain alterations (either present initially or developing simultaneously). To date, however, large-scale, prospective longitudinal studies of PTSD symptom trajectories that involve repeated cognitive and neuroimaging assessment are critically missing.
My doctoral research was designed as an observational prospective study of consecutive trauma survivors admitted to a general hospital’s emergency department (ED) following traumatic incidents. The overarching goal was to uncover the neurocognitive moderators underlying PTSD symptom trajectories. To achieve this goal, we repeatedly and simultaneously evaluated trauma survivors’ clinical symptoms, cognitive functioning, brain structure and function, at 1-, 6-, and 14-months following trauma exposure. Results can be organized into three objectives.
First, we utilized advanced computational methodology to characterize and classify individuals within 1-month following trauma, based on the collected multi-parametric measurements. We successfully identified subgroups of individuals (significantly related to PTSD clinical diagnosis, but not identical to it), with a unique set of potential mechanism-related cognitive and neural biomarkers differentiating between them, in line with previously documented PTSD literature. Second, we investigated which objective multi-parametric indices, collected shortly after trauma exposure, could be of value in predicting individuals’ long-term clinical PTSD symptoms. We found both a cognitive construct which emerged as a significant predictor of PTSD development (i.e., cognitive flexibility), as well as neuroanatomical risk factors for PTSD severity (i.e., hippocampus and cavum septum pellucidum volumes), both of which could guide early management and objective long-term monitoring. Finally, we elucidated the neurobehavioral mechanisms underlying motivational processing in PTSD development. During a competitive decision-making paradigm, we found that increased behavioral risk-aversion and imbalanced neural responsivity to punishments vs. rewards, early after trauma, were predictive of PTSD symptoms 13-months later on. Specifically, hyperactive amygdala in response to punishments predicted hyperarousal symptoms, whereas hypoactive ventral striatum in response to rewards predicted subsequent avoidance symptoms.
In summary, by linking observed symptoms with cognitive functioning and neural alternations, findings from this thesis work enhanced our understating of the nature of traumatic stress responses and its aftermath, informing both the pathogenesis of PTSD and the science of resilience and recovery from trauma. Lower cognitive flexibility in PTSD might be manifested as imbalanced neural responsivity to positive vs. negative valance stimuli, potentially involving key brain structures such as the hippocampus and the amygdala. Future studies using similar integrative, mechanism-oriented, exploratory approaches, may lead to improved early treatment and prevention of PTSD, thus improving life of trauma survivors and increasing cost-effectiveness of personalized interventions.
Anxiety Disorders; Biology; Decision Making; Emotions; Motivation; Psychiatry; Psychology; Punishment; Reward; Stress Disorders, Post-Traumatic; Stress, Psychological; Neuroimaging; Functional Neuroimaging