title: Conflict anticipation in alcohol dependence - A model-based fMRI study of stop signal task.
abstract: BACKGROUND
  Our previous work characterized altered cerebral activations during cognitive control in individuals with alcohol dependence (AD). A hallmark of cognitive control is the ability to anticipate changes and adjust behavior accordingly. Here, we employed a Bayesian model to describe trial-by-trial anticipation of the stop signal and modeled fMRI signals of conflict anticipation in a stop signal task. Our goal is to characterize the neural correlates of conflict anticipation and its relationship to response inhibition and alcohol consumption in AD.
  
  
  METHODS
  Twenty-four AD and 70 age and gender matched healthy control individuals (HC) participated in the study. fMRI data were pre-processed and modeled with SPM8. We modeled fMRI signals at trial onset with individual events parametrically modulated by estimated probability of the stop signal, p(Stop), and compared regional responses to conflict anticipation between AD and HC. To address the link to response inhibition, we regressed whole-brain responses to conflict anticipation against the stop signal reaction time (SSRT).
  
  
  RESULTS
  Compared to HC (54/70), fewer AD (11/24) showed a significant sequential effect - a correlation between p(Stop) and RT during go trials - and the magnitude of sequential effect is diminished, suggesting a deficit in proactive control. Parametric analyses showed decreased learning rate and over-estimated prior mean of the stop signal in AD. In fMRI, both HC and AD responded to p(Stop) in bilateral inferior parietal cortex and anterior pre-supplementary motor area, although the magnitude of response increased in AD. In contrast, HC but not AD showed deactivation of the perigenual anterior cingulate cortex (pgACC). Furthermore, deactivation of the pgACC to increasing p(Stop) is positively correlated with the SSRT in HC but not AD. Recent alcohol consumption is correlated with increased activation of the thalamus and cerebellum in AD during conflict anticipation.
  
  
  CONCLUSIONS
  The current results highlight altered proactive control that may serve as an additional behavioral and neural marker of alcohol dependence.
authors.affiliation: Department of Psychiatry, Yale University School of Medicine, New Haven, CT 06519, USA.
authors.forename: Sien
authors.initials: S
authors.lastname: Hu
authors.affiliation: Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794, USA.
authors.forename: Jaime S
authors.initials: JS
authors.lastname: Ide
authors.affiliation: Department of Psychiatry, Yale University School of Medicine, New Haven, CT 06519, USA.
authors.forename: Sheng
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Department of Psychiatry, Yale University School of Medicine, New Haven, CT 06519, USA ; Department of Neurobiology, Yale University School of Medicine, New Haven, CT 06520, USA ; Child Study Center, Yale University School of Medicine, New Haven, CT 06520, USA.
authors.forename: Rajita
authors.initials: R
authors.lastname: Sinha
authors.affiliation: Department of Psychiatry, Yale University School of Medicine, New Haven, CT 06519, USA ; Department of Neurobiology, Yale University School of Medicine, New Haven, CT 06520, USA ; Interdepartmental Neuroscience Program, Yale University School of Medicine, New Haven, CT 06520, USA.
authors.forename: Chiang-Shan R
authors.initials: CS
authors.lastname: Li
mesh_terms: D000328:Adult; D000437:Alcoholism / Q000503:physiopathology*; D059031:Anticipation, Psychological / Q000502:physiology*; D001499:Bayes Theorem; D002540:Cerebral Cortex / Q000503:physiopathology*; D003220:Conflict, Psychological; D056344:Executive Function / Q000502:physiology*; D005260:Female; D006801:Humans; D007266:Inhibition, Psychological; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D008960:Models, Psychological; D011597:Psychomotor Performance / Q000502:physiology*
keywords: Alcoholism; Cognitive control; Conflict; Medial prefrontal cortex; Neuroimaging