Erin C Dowd

Washington University in St. Louis, Saint Louis, MO, United States

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Publications (5)30.26 Total impact

  • 01/2013: pages TBD;
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    Erin C Dowd, Deanna M Barch
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    ABSTRACT: Reward processing abnormalities have been implicated in the pathophysiology of negative symptoms such as anhedonia and avolition in schizophrenia. However, studies examining neural responses to reward anticipation and receipt have largely relied on instrumental tasks, which may confound reward processing abnormalities with deficits in response selection and execution. 25 chronic, medicated outpatients with schizophrenia and 20 healthy controls underwent functional magnetic resonance imaging using a pavlovian reward prediction paradigm with no response requirements. Subjects passively viewed cues that predicted subsequent receipt of monetary reward or non-reward, and blood-oxygen-level-dependent signal was measured at the time of cue presentation and receipt. At the group level, neural responses to both reward anticipation and receipt were largely similar between groups. At the time of cue presentation, striatal anticipatory responses did not differ between patients and controls. Right anterior insula demonstrated greater activation for nonreward than reward cues in controls, and for reward than nonreward cues in patients. At the time of receipt, robust responses to receipt of reward vs. nonreward were seen in striatum, midbrain, and frontal cortex in both groups. Furthermore, both groups demonstrated responses to unexpected versus expected outcomes in cortical areas including bilateral dorsolateral prefrontal cortex. Individual difference analyses in patients revealed an association between physical anhedonia and activity in ventral striatum and ventromedial prefrontal cortex during anticipation of reward, in which greater anhedonia severity was associated with reduced activation to money versus no-money cues. In ventromedial prefrontal cortex, this relationship held among both controls and patients, suggesting a relationship between anticipatory activity and anhedonia irrespective of diagnosis. These findings suggest that in the absence of response requirements, brain responses to reward receipt are largely intact in medicated individuals with chronic schizophrenia, while reward anticipation responses in left ventral striatum are reduced in those patients with greater anhedonia severity.
    PLoS ONE 01/2012; 7(5):e35622. · 3.73 Impact Factor
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    ABSTRACT: Emotional dysfunction has long been established as a critical clinical feature of schizophrenia. In the past decade, there has been extensive work examining the potential contribution of abnormal amygdala activation to this dysfunction in patients with schizophrenia. A number of studies have demonstrated under-recruitment of the amygdala in response to emotional stimuli, while others have shown intact recruitment of this region. To date, there have been few attempts to synthesize this literature using quantitative criteria or to use a formal meta-analytic approach to examine which variables may moderate the magnitude of between-group differences in amygdala activation in response to aversive emotional stimuli. We conducted a meta-analysis of amygdala activation in patients with schizophrenia, using a bootstrapping approach to investigate: (a) evidence for amygdala under-recruitment in schizophrenia and (b) variables that may moderate the magnitude of between-group differences in amygdala activation. We demonstrate that patients with schizophrenia show statistically significant, but modest, under-recruitment of bilateral amygdala (mean effect size = -0.20 SD). However, present findings indicate that this under-recruitment is dependent on the use of a neutral vs emotion interaction contrast and is not apparent if amygdala activation by patients and controls is evaluated in a negative emotional condition only.
    Schizophrenia Bulletin 12/2010; 38(3):608-21. · 8.80 Impact Factor
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    Deanna M Barch, Erin C Dowd
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    ABSTRACT: The past several years have seen a resurgence of interest in understanding the psychological and neural bases of what are often referred to as "negative symptoms" in schizophrenia. These aspects of schizophrenia include constructs such as asociality, avolition (a reduction in the motivation to initiate or persist in goal-directed behavior), and anhedonia (a reduction in the ability to experience pleasure). We believe that these dimensions of impairment in individuals with schizophrenia reflect difficulties using internal representations of emotional experiences, previous rewards, and motivational goals to drive current and future behavior in a way that would allow them to obtain desired outcomes, a deficit that has major clinical significance in terms of functional capacity. In this article, we review the major components of the systems that link experienced and anticipated rewards with motivated behavior that could potentially be impaired in schizophrenia. We conclude that the existing evidence suggests relatively intact hedonics in schizophrenia, but impairments in some aspects of reinforcement learning, reward prediction, and prediction error processing, consistent with an impairment in "wanting." As of yet, there is only indirect evidence of impairment in anterior cingulate and orbital frontal function that may support value and effort computations. However, there are intriguing hints that individuals with schizophrenia may not be able to use reward information to modulate cognitive control and dorsolateral prefrontal cortex function, suggesting a potentially important role for cortical-striatal interactions in mediating impairment in motivated and goal-directed behavior in schizophrenia.
    Schizophrenia Bulletin 09/2010; 36(5):919-34. · 8.80 Impact Factor
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    Erin C Dowd, Deanna M Barch
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    ABSTRACT: Emotional impairments such as anhedonia are often considered key features of schizophrenia. However, self-report research suggests that emotional experience in response to affect-eliciting stimuli is intact in schizophrenia. Investigation of neural activity during emotional experience may help clarify whether symptoms of anhedonia more likely reflect alterations of in-the-moment hedonic experience or impairments in other aspects of goal-directed behavior. Forty individuals with DSM-IV-TR schizophrenia or schizoaffective disorder and 32 healthy control subjects underwent functional magnetic resonance imaging while making valence and arousal ratings in response to emotional pictures, words, and faces. Blood oxygen level-dependent responses were compared between patients and control subjects and were correlated with questionnaire measures of anhedonia. Patients showed some evidence of blunted valence but not arousal ratings in response to emotional stimuli compared with control subjects. Higher anhedonia scores were associated with blunted valence ratings in both groups and fully mediated the group differences in valence ratings. Functional activity was largely intact in patients, except for regions in right ventral striatum and left putamen, which showed reduced responses to positive stimuli. Higher anhedonia was associated with reduced activation to positive versus negative stimuli in bilateral amygdala and right ventral striatum in patients and in bilateral caudate in control subjects. Increased anhedonia is associated with a reduced experience of valence in both patients and control subjects, and group differences in experienced valence are likely driven by individual differences in anhedonia. Reduced activation of the striatum and amygdala may contribute to symptoms of anhedonia by failing to signal the salience of positive events.
    Biological psychiatry 12/2009; 67(10):902-11. · 8.93 Impact Factor