Person: Bogdan, Ryan
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Bogdan
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Bogdan, Ryan
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Publication Increased Perceived Stress is Associated with Blunted Hedonic Capacity: Potential Implications for Depression Research(Elsevier Science, 2007) Pizzagalli, Diego; Bogdan, Ryan; Ratner, Kyle G.; Jahn, Allison L.Preclinical studies suggest that stress exerts depressogenic effects by impairing hedonic capacity, in humans, however, the precise mechanisms linking stress and depression are largely unknown. As an initial step towards better understanding the association between stress and anhedonia, the present study tested, in two independent samples, whether individuals reporting elevated stress exhibit decreased hedonic capacity. The Perceived Stress Scale (PSS) measured the decree to which participants appraised their daily life as unpredictable, uncontrollable, and overwhelming. Hedonic capacity was objectively assessed using a signal-detection task based on a differential reinforcement schedule. Decreased reward responsiveness (i.e., the participants propensity to modulate behavior as a function of reward) was used as an operational measure of hedonic capacity. In both Study 1 (n = 88) and Study 2 (n = 80), participants with high PSS scores displayed blunted reward responsiveness and reported elevated anhedonic symptoms. Additionally, PSS scores predicted reduced reward responsiveness even after controlling for general distress and anxiety symptoms. These findings are consistent with preclinical data highlighting links between stress and anhedonia, and offer promising insights into potential mechanisms linking stress to depression.Publication Reduced Caudate and Nucleus Accumbens Response to Rewards in Unmedicated Subjects with Major Depressive Disorder(American Psychiatric Association, 2009) Pizzagalli, Diego; Holmes, Avram J.; Dillon, Daniel G.; Goetz, Elena L.; Birk, Jeffrey L.; Bogdan, Ryan; Dougherty, Darin D.; Iosifescu, Dan V.; Rauch, Scott L.; Fava, MaurizioObjective: Major depressive disorder is characterized by impaired reward processing, possibly due to dysfunction in the basal ganglia. However, few neuroimaging studies of depression have distinguished between anticipatory and consummatory phases of reward processing. Using functional MRI (fMRI) and a task that dissociates anticipatory and consummatory phases of reward processing, the authors tested the hypothesis that individuals with major depression would show reduced reward-related responses in basal ganglia structures. Method: A monetary incentive delay task was presented to 30 unmedicated individuals with major depressive disorder and 31 healthy comparison subjects during fMRI scanning. Whole-brain analyses focused on neural responses to reward-predicting cues and rewarding outcomes (i.e., monetary gains). Secondary analyses focused on the relationship between anhedonic symptoms and basal ganglia volumes. Results: Relative to comparison subjects, participants with major depression showed significantly weaker responses to gains in the left nucleus accumbens and the caudate bilaterally. Group differences in these regions were specific to rewarding outcomes and did not generalize to neutral or negative outcomes, although relatively reduced responses to monetary penalties in the major depression group emerged in other caudate regions. By contrast, evidence for group differences during reward anticipation was weaker, although participants with major depression showed reduced activation to reward cues in a small sector of the left posterior putamen. In the major depression group, anhedonic symptoms and depression severity were associated with reduced caudate volume bilaterally. Conclusions: These results suggest that basal ganglia dysfunction in major depression may affect the consummatory phase of reward processing. Additionally, morphometric results suggest that anhedonia in major depression is related to caudate volume.Publication Enhanced Negative Feedback Responses in Remitted Depression(Lippincott Williams & Wilkins, 2008) Santesso, Diane L.; Steele, Katherine T.; Bogdan, Ryan; Holmes, Avram J.; Deveney, Christen M.; Meites, Tiffany M.; Pizzagalli, DiegoMajor depressive disorder (MDD)is characterized by hypersensitivity to negative feedback that might involve frontocingulate dysfunction. MDD patients exhibit enhanced electrophysiological responses to negative internal (errors) and external (feedback) cues. Whether this dysfunction extends to remitted depressed (RD) individuals with a history of MDD is currently unknown. To address this issue, we examined the feedback-related negativity in RD and control participants using a probabilistic punishment learning task. Despite equivalent behavioral performance, RD participants showed larger feedback-related negativities to negative feedback relative to controls; group differences remained after accounting for residual anxiety and depressive symptoms. The present findings suggest that abnormal responses to negative feedback extend to samples at increased risk for depressive episodes in the absence of current symptoms.Publication The Heritability of Hedonic Capacity and Perceived Stress: A Twin Study Evaluation of Candidate Depressive Phenotypes(Cambridge University Press, 2009) Bogdan, Ryan; Pizzagalli, DiegoBackground. Anhedonia and stress sensitivity have been identified as promising depressive phenotypes. Research suggests that stress-induced anhedonia is a possible mechanism underlying the association between stress and depression. The present proof-of-concept study assessed whether hedonic capacity and stress perception are heritable and whether their genetic and environmental contributions are shared. Method. Twenty monozygotic (MZ) and 15 dizygotic (DZ) twin pairs completed a probabilistic reward task that provides an objective behavioral measure of hedonic capacity (reward responsiveness) and completed several questionnaires including the Perceived Stress Scale (PSS). Bivariate Cholesky models were used to investigate whether covariation between (1) depressive symptoms and hedonic capacity, (2) depressive symptoms and perceived stress, and (3) perceived stress and hedonic capacity resulted from shared or residual genetic and environmental factors. Results. Additive genetic (A) and individual-specific environment (E) factors contributed to 46% and 54% of the variance in hedonic capacity, respectively. For perceived stress, 44% and 56%, of the variance was accounted for by A and E factors, respectively. The genetic correlation between depression and hedonic capacity was moderate (r(a)=0.29), whereas the correlation between depression and stress perception was large (r(a)=0.67). Genetic and environmental correlations between hedonic capacity and stress perception were large (r(a)=0.72 and r(e)= -0.43). Conclusions. The present study provides initial feasibility for using a twin approach to investigate genetic contributions of a laboratory-based anhedonic phenotype. Although these preliminary findings indicate that hedonic capacity and perceived stress are heritable, with substantial shared additive genetic contributions, replications in larger samples will be needed.Publication Dissociation of Neural Regions Associated with Anticipatory Versus Consummatory Phases of Incentive Processing(Blackwell Publishers, 2008) Bogdan, Ryan; Wald, Lawrence L.; Holmes, A; Jahn, Allison L.; Pizzagalli, Diego; Wald, Lawrence; Dillon, DanielIncentive delay tasks implicate the striatum and medial frontal cortex in reward processing. However, prior studies delivered more rewards than penalties, possibly leading to unwanted differences in signal-to-noise ratio. Also, whether particular brain regions are specifically involved in anticipation or consumption is unclear. We used a task featuring balanced incentive delivery and an analytic strategy designed to identify activity specific to anticipation or consumption. Reaction time data in two independent samples (n = 13 and n = 8) confirmed motivated responding. Functional magnetic resonance imaging revealed regions activated by anticipation (anterior cingulate) versus consumption (orbital and medial frontal cortex). Ventral striatum was active during reward anticipation but not significantly more so than during consumption. Although the study features several methodological improvements and helps clarify the neural basis of incentive processing, replications in larger samples are needed.Publication Individual Differences in Reinforcement Learning: Behavioral, Electrophysiological, and Neuroimaging Correlates(Elsevier, 2008) Santesso, Diane L.; Dillon, Daniel G.; Birk, Jeffrey L.; Holmes, Avram J.; Goetz, Elena; Bogdan, Ryan; Pizzagalli, DiegoDuring reinforcement learning, phasic modulations of activity in midbrain dopamine neurons are conveyed to the dorsal anterior cingulate Cortex (dACC) and basal ganglia (BG) and serve to guide adaptive responding. While the animal literature supports a role for the dACC in integrating reward history over time, most human electrophysiological Studies of dACC function have focused on responses to single positive and negative outcomes. The present electrophysiological study investigated the role of the dACC in probabilistic reward learning in healthy subjects using a task that required integration of reinforcement history over time. We recorded the feedback-related negativity (FRN) to reward feedback in subjects who developed a response bias toward a more frequently rewarded ("rich") stimulus ("learners") versus subjects who did not ("non-learners"). Compared to non-learners, learners showed more positive (i.e., smaller) FRNs and greater dACC activation upon receiving reward for correct identification of the rich stimulus. In addition, dACC activation and a bias to select the rich Stimulus were positively correlated. The same participants also completed a monetary incentive delay (MID) task administered during functional magnetic resonance imaging. Compared to non-learners, learners displayed stronger BG responses to reward in the MID task. These findings raise the possibility that learners in the probabilistic reinforcement task were characterized by stronger dACC and BG responses to rewarding outcomes. Furthermore, these results highlight the importance of the dACC to probabilistic reward learning in humans.Publication Acute Stress Reduces Reward Responsiveness: Implications for Depression(Elsevier, 2006) Bogdan, Ryan; Pizzagalli, DiegoBackground: Stress, one of the strongest risk factors for depression, has been linked to "anbedonic" behavior and dysfunctional reward-related neural circuitry in preclinical models. Methods: To test if acute stress reduces reward responsiveness (i.e., the ability to modulate behavior as a function of past reward), a signal-detection task coupled with a differential reinforcement schedule was utilized. Eighty female participants completed the task under both a stress condition, either threat-of-shock (h = 38) or negative performance feedback (h = 42), and a no-stress condition. Results: Stress increased negative affect and anxiety. As hypothesized based on preclinical findings, stress, particularly the threat-of-shock condition, impaired reward responsiveness. Regression analyses indicate that self-report measures of anbedonia predicted stress-induced hedonic deficits even after controlling for anxiety symptoms. Conclusions: These findings indicate that acute stress reduces reward responsiveness, particularly in individuals with anhedonic symptoms. Stress-induced hedonic deficit is a promising candidate mechanism linking stressful experiences to depression.