Anxiety disorders are the most common form of pediatric psychopathology, affecting 5 - 20% of children and adolescents. Despite therapeutic advances, treatment-resistance remains high, and progress towards early detection of at-risk populations and more effective treatments has stalled. Although some anxiety disorders are transient, recent studies suggest that pediatric anxiety disorders commonly persist into adulthood. Because anxiety disorders are costly and debilitating conditions that are very often associated with other severe psychopathology such as substance abuse, depression and suicidality, there is an imperative need to identify risk and resilience factors that moderate pediatric anxiety and improve treatment.
Fear conditioning and resistance to extinction are two domains that have been implicated in the etiology and maintenance of anxiety disorders. Indeed, one of the most effective treatment for pediatric and adult anxiety disorders, exposure therapy, relies profoundly on extinction learning. The proposed research plan will investigate the neural correlates of aberrant fear conditioning and extinction processes in children and adolescents with anxiety disorders.
The proposed research aims to isolate brain-based information-processing mechanisms implicated in perturbed fear learning and extinction characteristic of pediatric anxiety. A fMRI study using a novel age-appropriate fear conditioning-extinction paradigm are proposed. The study will delineate perturbed psychological and psychophysiological response to fear conditioning and isolate neuro-cognitive mechanisms mediating extinction recall in anxious and non-anxious children. Three weeks after completing fear conditioning and extinction task in the psychophysiology lab, participants will return to complete an fMRI extinction-recall task quantifying responses to extinguished CS blends. Two major hypotheses will be examined: a) anxious children will exhibit perturbations during extinction as measured by psychophysiology indexes and self-reported fear compared to non-anxious children; b) less activation in ventromedial prefrontal cortex (vmPFC) is expected in anxious, relative to healthy, children during extinction-recall. Furthermore, the study will focus on the therapeutic relevance of dysfunction in fear learning and extinction for treatment by examining the associations between vmPFC function and response to exposure intervention in anxious children. Lower levels of vmPFC activation prior to exposure therapy and larger pre-to-post-treatment changes in vmPFC activity are expected to be associated with better response to exposure therapy.
