Effects of Psychopathology on Goal-Oriented Behavior
Understanding the contributions of prefrontal brain systems in controlling behavior during goal-oriented tasks has direct applications to the characterization and treatment of certain psychiatric disorders. Current research has revealed a selective hypometabolic activity of certain regions in the anterior cingulate cortex (ACC), dorsolateral prefrontal cortex (DLPFC), or orbitofrontal cortex (OFC) in depression, as evident in a number of positron emission tomography (PET), functional neuroimaging (fMRI), and single photonemission computerized tomography (SPECT) studies. However, the exact implication of frontostriatal circuits in symptom manifestation in the disorder remains unknown. Among the current research aims of the lab, facilitated by a recently awarded Frontiers pilot grant, is to establish a translational research program that explores the relations between the deficient cognitive profile in depression—particularly during purposeful behavior (i.e., disruptions in normal cognitive and motor inhibition, attentional disturbances, impulsivity)—and a physiological profile characterized by PFC-limbic system abnormalities. We are currently exploring these relationships in a study employing transcranial direct current stimulation (tDCS) as well as functional magnetic resonance imaging (fMRI). The long-term objective of the lab is to identify how an understanding of these relationships can have functional implications for the diagnosis and treatment of depression, as well as other psychiatric syndromes characterized by prefrontal cortex hypofunction such as attention-deficit-hyperactivity- disorder (ADHD) and obsessive-compulsive disorder (OCD). Specifically, our goal is to employ a new combination of methodologies, including behavioral, functional and perfusion MRI, tDCS, as well as neuropsychological/clinical studies, in order to establish more detailed neurocognitive assessments of hypofrontal functioning in depression that will allow for better characterization of different patient subgroups. The complementarity of these approaches has the potential to improve our understanding of basic behavioral processes and PFC involvement in cognitive tasks, as well as patients’ functional abilities in depression beyond the insights provided by traditional psychometric or structural imaging measures. Our aim is to apply knowledge from basic neuroscience toward the development of a comprehensive set of neurocognitive assessment procedures; such procedures will allow for a better characterization of different populations of patients diagnosed with depression and other disorders based on lateral PFC hypo-functioning and will permit specific predictions on the effectiveness and outcome of different treatment plans.