In recent years, many researchers have been interested in discovering a neuropsychological basis of emotion and emotional disorders. One of the more widely studied of these models has been Davidson's approach-withdrawal model (Davidson, 1998), which posits two separate neural systems of motivation and emotion and hypothesizes that these systems are responsible for individual differences in reactivity to emotional stimuli, or """"""""affective styles."""""""" The model also proposes that abnormalities in these systems play an etiological role in emotional disorders: depression is characterized by a deficit in reward seeking behavior (i.e., approach motivation) and anxiety is characterized by a tendency to withdraw from aversive stimuli (i.e., withdrawal motivation). These abnormalities are also hypothesized to be associated with specific asymmetries in frontal activation (depression = decrease in left frontal; anxiety = increase in right frontal). While several researchers have found support for this model, no study has directly tested whether the hypothesized frontal asymmetry reflects this """"""""low approach style"""""""" in depression. This project will be able to test this hypothesis by comparing the EEG activation of depressed and non-depressed individuals during tasks that manipulate approach and withdrawal motivation. This study will also be able to explore whether the relationship between motivation and EEG asymmetry is different for individuals with particular clinical characteristics (e.g., a comorbid anxiety disorder, chronic depression). This project will not only be able to address the relationship between motivation and depression but will also further the understanding of the heterogeneity of depression by teasing apart its biological correlates. ? ?
