291 Psychology Building
College Station, TX 77843-4235
Neural mechanisms underlying internal control of behavior
In the real-world our behavior is often guided by our internal goals and intentions and cues in the environment. Often we have to shield our internal goals from external influences, such as when we are at the grocery store and walking past the dessert case. While this is an innocuous case of external information biasing our behavior, failures of overcoming such biases underlie many psychiatric and neurological disorders. For instance, in substance addiction, failing to suppress cues associated with taking drugs can lead to drug seeking behavior and relapse from treatment. However, the neural mechanisms underlying voluntary task choices are not well understood. My research uses multimodal neuroimaging techniques (structural and functional MRI, DTI, and EEG/ERP) to investigate the neural mechanisms that mediate between internal goal-directed behavior and externally directed behavior.
- In a study recently published in NeuroImage, we compared brain activity on task choices that were guided by internally-maintained goals and for task choices that were externally determined by the experimenter. We found that the frontal pole, or the most anterior portion of the prefrontal cortex was specifically activated by internal task choices. Further, we asked whether this same region was activated when overcoming external biases on goal-directed task choices. Indeed, the frontal pole was more more active when participants overcame the external biases than when they succumbed to such biases.
Brain connectivity supporting executive functions
Over the last decade, the field of human functional neuroimaging has shifted from a focus on identifying the function of individual brain regions to identifying the functional role of coordinated networks of brain regions. Psychotic symptoms develop during late adolescence, which is a critical time period for the development of white matter pathways.As part of the ADAPT program at the University of Colorado Boulder, I am interested in identifying disrupted brain connectivity in individuals at a risk for developing psychotic disorders such as schizophrenia. This work utilizes both functional connectivity measures (e.g., resting-state connectivity) and structural connectivity measures (e.g., probabilistic tractography and fractional anisotropy (FA)).
- We recently found that functional connectivity is disrupted even in adolescents that manifest sub-clinical levels of psychotic symptoms (Orr, Turner, & Mittal, 2014, NeuroImage:Clinical). These disruptions were observed in many of the same networks that are disrupted in schizophrenia, supporting the hypothesis that psychosis occurs along a spectrum. This sub-clinical population represents a key population for understanding the psychogenesis of psychotic disorders.