@article{BaltaBeylergilBeckDesernoetal.2017,
  author    = {Balta Beylergil, Sinem and Beck, Anne and Deserno, Lorenz and Lorenz, Robert C. and Rapp, Michael Armin and Schlagenhauf, Florian and Heinz, Andreas and Obermayer, Klaus},
  title     = {Dorsolateral prefrontal cortex contributes to the impaired behavioral adaptation in alcohol dependence},
  series = {NeuroImage: Clinical : a journal of diseases affecting the nervous system},
  volume    = {15},
  journal   = {NeuroImage: Clinical : a journal of diseases affecting the nervous system},
  publisher = {Elsevier},
  address   = {Oxford},
  issn      = {2213-1582},
  doi       = {10.1016/j.nicl.2017.04.010},
  pages     = {80 -- 94},
  year      = {2017},
  abstract  = {Substance-dependent individuals often lack the ability to adjust decisions flexibly in response to the changes in reward contingencies. Prediction errors (PEs) are thought to mediate flexible decision-making by updating the reward values associated with available actions. In this study, we explored whether the neurobiological correlates of PEs are altered in alcohol dependence. Behavioral, and functional magnetic resonance imaging (fMRI) data were simultaneously acquired from 34 abstinent alcohol-dependent patients (ADP) and 26 healthy controls (HC) during a probabilistic reward-guided decision-making task with dynamically changing reinforcement contingencies. A hierarchical Bayesian inference method was used to fit and compare learning models with different assumptions about the amount of task-related information subjects may have inferred during the experiment. Here, we observed that the best-fitting model was a modified Rescorla-Wagner type model, the "double-update" model, which assumes that subjects infer the knowledge that reward contingencies are anti-correlated, and integrate both actual and hypothetical outcomes into their decisions. Moreover, comparison of the best-fitting model's parameters showed that ADP were less sensitive to punishments compared to HC. Hence, decisions of ADP after punishments were loosely coupled with the expected reward values assigned to them. A correlation analysis between the model-generated PEs and the fMRI data revealed a reduced association between these PEs and the BOLD activity in the dorsolateral prefrontal cortex (DLPFC) of ADP. A hemispheric asymmetry was observed in the DLPFC when positive and negative PE signals were analyzed separately. The right DLPFC activity in ADP showed a reduced correlation with positive PEs. On the other hand, ADP, particularly the patients with high dependence severity, recruited the left DLPFC to a lesser extent than HC for processing negative PE signals. These results suggest that the DLPFC, which has been linked to adaptive control of action selection, may play an important role in cognitive inflexibility observed in alcohol dependence when reinforcement contingencies change. Particularly, the left DLPFC may contribute to this impaired behavioral adaptation, possibly by impeding the extinction of the actions that no longer lead to a reward.},
  language  = {en}
}
@article{SeboldNebeGarbusowetal.2017,
  author    = {Sebold, Miriam Hannah and Nebe, Stephan and Garbusow, Maria and Guggenmos, Matthias and Schad, Daniel and Beck, Anne and Kuitunen-Paul, S{\"o}ren and Sommer, Christian and Frank, Robin and Neu, Peter and Zimmermann, Ulrich S. and Rapp, Michael Armin and Smolka, Michael N. and Huys, Quentin J. M. and Schlagenhauf, Florian and Heinz, Andreas},
  title     = {When Habits Are Dangerous: Alcohol Expectancies and Habitual Decision Making Predict Relapse in Alcohol Dependence},
  series = {Biological psychiatry : a journal of psychiatric neuroscience and therapeutics ; a publication of the Society of Biological Psychiatry},
  volume    = {82},
  journal   = {Biological psychiatry : a journal of psychiatric neuroscience and therapeutics ; a publication of the Society of Biological Psychiatry},
  publisher = {Elsevier},
  address   = {New York},
  issn      = {0006-3223},
  doi       = {10.1016/j.biopsych.2017.04.019},
  pages     = {847 -- 856},
  year      = {2017},
  abstract  = {BACKGROUND: Addiction is supposedly characterized by a shift from goal-directed to habitual decision making, thus facilitating automatic drug intake. The two-step task allows distinguishing between these mechanisms by computationally modeling goal-directed and habitual behavior as model-based and model-free control. In addicted patients, decision making may also strongly depend upon drug-associated expectations. Therefore, we investigated model-based versus model-free decision making and its neural correlates as well as alcohol expectancies in alcohol-dependent patients and healthy controls and assessed treatment outcome in patients. METHODS: Ninety detoxified, medication-free, alcohol-dependent patients and 96 age-and gender-matched control subjects underwent functional magnetic resonance imaging during the two-step task. Alcohol expectancies were measured with the Alcohol Expectancy Questionnaire. Over a follow-up period of 48 weeks, 37 patients remained abstinent and 53 patients relapsed as indicated by the Alcohol Timeline Followback method. RESULTS: Patients who relapsed displayed reduced medial prefrontal cortex activation during model-based decision making. Furthermore, high alcohol expectancies were associated with low model-based control in relapsers, while the opposite was observed in abstainers and healthy control subjects. However, reduced model-based control per se was not associated with subsequent relapse. CONCLUSIONS: These findings suggest that poor treatment outcome in alcohol dependence does not simply result from a shift from model-based to model-free control but is instead dependent on the interaction between high drug expectancies and low model-based decision making. Reduced model-based medial prefrontal cortex signatures in those who relapse point to a neural correlate of relapse risk. These observations suggest that therapeutic interventions should target subjective alcohol expectancies.},
  language  = {en}
}
@article{FriedelSchlagenhaufBecketal.2015,
  author    = {Friedel, Eva and Schlagenhauf, Florian and Beck, Anne and Dolan, Raymond J. and Huys, Quentin J. M. and Rapp, Michael Armin and Heinz, Andreas},
  title     = {The effects of life stress and neural learning signals on fluid intelligence},
  series = {European archives of psychiatry and clinical neuroscience : official organ of the German Society for Biological Psychiatry},
  volume    = {265},
  journal   = {European archives of psychiatry and clinical neuroscience : official organ of the German Society for Biological Psychiatry},
  number    = {1},
  publisher = {Springer},
  address   = {Heidelberg},
  issn      = {0940-1334},
  doi       = {10.1007/s00406-014-0519-3},
  pages     = {35 -- 43},
  year      = {2015},
  abstract  = {Fluid intelligence (fluid IQ), defined as the capacity for rapid problem solving and behavioral adaptation, is known to be modulated by learning and experience. Both stressful life events (SLES) and neural correlates of learning [specifically, a key mediator of adaptive learning in the brain, namely the ventral striatal representation of prediction errors (PE)] have been shown to be associated with individual differences in fluid IQ. Here, we examine the interaction between adaptive learning signals (using a well-characterized probabilistic reversal learning task in combination with fMRI) and SLES on fluid IQ measures. We find that the correlation between ventral striatal BOLD PE and fluid IQ, which we have previously reported, is quantitatively modulated by the amount of reported SLES. Thus, after experiencing adversity, basic neuronal learning signatures appear to align more closely with a general measure of flexible learning (fluid IQ), a finding complementing studies on the effects of acute stress on learning. The results suggest that an understanding of the neurobiological correlates of trait variables like fluid IQ needs to take socioemotional influences such as chronic stress into account.},
  language  = {en}
}