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ndltd-OhioLink-oai-etd.ohiolink.edu-ucin12416257282021-08-03T06:13:08Z Neural Correlates of Impulsivity and Risk Taking in Bipolar Disorder Lamy, Martine Bipolar disorder is a psychiatric illness characterized by mood lability, cognitive difficulties, and impulsive behaviors and is the sixth leading cause of disability worldwide. Neuroimaging work suggests that dysfunction of ventral-prefrontal-striatal-thalamic circuits (termed the 'Anterior Limbic Network' or ALN), which modulate emotional and social behavior may lead to the disruption in emotional homeostasis present in the disorder. Impulsive behavior results from abnormalities in brain systems guiding attention, inhibition, and decision making processes. Regions within the ALN have previously been implicated in decision making relating to reward and risk taking in healthy subjects. Therefore the aims of the present study were threefold: (1) to characterize impulsivity relating to risk and reward-mediated decision making in bipolar disorder, (2) to determine whether ALN abnormalities underlie impulsivity relating to reward valuation in bipolar disorder, and (3) to determine whether ALN abnormalities underlie greater risk taking in bipolar disorder. In order to investigate these aims, twenty euthymic bipolar patients and twenty-five demographically matched healthy subjects were recruited to participate in a series of behavioral and/or fMRI tasks designed to assess different dimensions of impulsivity. Euthymic bipolar subjects exhibited elevated levels of self-reported impulsivity, and deficits in response execution as compared to healthy subjects. In contrast, euthymic bipolar subjects and healthy subjects performed similarly on tasks designed to assess reward valuation and risk taking propensity. However, despite similar behavioral performance on these tasks, bipolar subjects demonstrated alterations in brain activity within the ALN. Specifically, bipolar subjects demonstrated significantly less activation than healthy subjects during reward valuation in bilateral striatum, bilateral thalamus, bilateral amygdala, bilateral globus pallidus, and the right inferior frontal gyrus. Conversely, bipolar subjects demonstrated increased activation as compared to healthy subjects in the right inferior frontal gyrus and left globus pallidus during a risk taking task. These results provide evidence that impulsive behavior during the euthymic mood state of bipolar disorder may be related to deficits in rapid information processing, rather than a failure of reward-mediated decision making processes. In addition, the abnormalities within the ALN in bipolar subjects during task performance may underlie behavioral manifestations of impulsive behavior that lie outside of the explicit decision making processes required for performance of laboratory based impulsivity measures. Future work investigating the role of reward-mediated decision making in impulsive behavior should be conducted across mood states in bipolar disorder in order to identify state- and trait-related components of impulsive decision making. 2009-07-14 English text University of Cincinnati / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=ucin1241625728 http://rave.ohiolink.edu/etdc/view?acc_num=ucin1241625728 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.
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NDLTD
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English
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NDLTD
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| author |
Lamy, Martine
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Lamy, Martine
Neural Correlates of Impulsivity and Risk Taking in Bipolar Disorder
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| author_facet |
Lamy, Martine
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| author_sort |
Lamy, Martine
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| title |
Neural Correlates of Impulsivity and Risk Taking in Bipolar Disorder
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| title_short |
Neural Correlates of Impulsivity and Risk Taking in Bipolar Disorder
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| title_full |
Neural Correlates of Impulsivity and Risk Taking in Bipolar Disorder
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| title_fullStr |
Neural Correlates of Impulsivity and Risk Taking in Bipolar Disorder
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| title_full_unstemmed |
Neural Correlates of Impulsivity and Risk Taking in Bipolar Disorder
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| title_sort |
neural correlates of impulsivity and risk taking in bipolar disorder
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University of Cincinnati / OhioLINK
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2009
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http://rave.ohiolink.edu/etdc/view?acc_num=ucin1241625728
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AT lamymartine neuralcorrelatesofimpulsivityandrisktakinginbipolardisorder
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1719432947726024704
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