BRAIN BEHAVIOR RELATIONSHIPS IN ANXIETY AND DEPRESSION

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In the project described in this proposal, I am examining the relationship between brain activity, as measured by EEG alpha, and the ability to perform a narrative task in depressed and anxious individuals. In my previous research, I have used behavioral methods to infer brain/behavior relationships (e.g., tachistoscopic presentation of stimuli to either the right or left visual field). This work has led to a model of brain functioning in emotion (Heller, 1990; 1993) that makes specific predictions about brain activity during depression and anxiety, with implications for the performance of behavioral tasks. In order to test the model, it became important to measure brain activity more directly. Therefore, I plan to examine patterns of EEG activity in conjunction with measuring behavioral functions with a narrative task. Evidence from studies employing EEG, blood flow and neuropsychological assessment suggests that different patterns of brain activity are associated with depression and anxiety. However, the results have been inconsistent, particularly with regard to the posterior region of the right hemisphere. One reason for this lack of clarity is likely to be that studies have not carefully separated depressed individuals with and without anxiety and vise versa. In the present study, I will examine brain activity in individuals in whom the degree of both depression and anxiety has been ascertained. It is hypothesized that depression and anxiety will each provide a unique contribution to the level of regional brain activity. In particular, high levels of anxiety are predicted to be correlated with high activity of right posterior regions; conversely, high levels of depression will be correlated with low right posterior activity. Since the patterns are hypothesized to be opposite, people who are both anxious and depressed are expected to display levels of activity midway between depressed and anxious subjects. In addition, because the right posterior region plays an important role in processing narrative information, level of activity in this area is predicted to correlate with performance on the behavioral task, with reduced activity associated with poorer performance. Given the fact that anxiety and depression often occur, it is likely that by clearly differentiating the degree to which each is present, we will be better able to discern the underlying patterns of brain activity that characterize these emotional states. The results may thus shed light on the failure in previous research to find consistent results for brain activity, particularly as measured over posterior regions. Furthermore, the behavioral task is of particular interest because narrative interchange is the most common mode of psychotherapy. The results are therefore likely to have implications regarding treatment efficacy in depressed and anxious individual.