Emotion, Depression, and Asymmetric Brain Function

180 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2006.Although numerous electroencephalography (EEG) studies have shown that depression is associated with abnormal functional asymmetries in frontal cortex, functional Magnetic Resonance Imaging (fMRI) and Positron Emission Tomography (PET) studies have largely failed to identify specific brain regions showing this effect. This failure likely stems in part from the widespread use of inappropriate data analytic strategies. The present project used a novel analytic strategy to test the hypothesis that emotion processes are related to asymmetric patterns of brain activity, particularly within dorsolateral prefrontal cortex (DLPFC). While collecting fMRI data, eleven depressed and eighteen control participants identified the color in which pleasant, neutral, and unpleasant words were printed. Both groups showed a rightward lateralization for unpleasant words within DLPFC. In a neighboring area of DLPFC, the depression group showed more right-lateralized activation than controls, replicating EEG findings. Lateralized patterns were also identified in amygdala and posterior cingulate gyrus. These findings confirm that emotional stimuli and trait depression are associated with asymmetric brain functions that are likely to go undetected unless appropriate data analytic procedures are used.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD