title: Resting-state activity in the left executive control network is associated with behavioral approach and is increased in substance dependence.
abstract: BACKGROUND
  Individuals with drug addictions report increased willingness to approach rewards. Approach behaviors are thought to involve executive control processes and are more strongly represented in the left compared to right prefrontal cortex. A direct link between approach tendencies and left hemisphere activity has not been shown in the resting brain. We hypothesized that compared to controls, substance dependent individuals (SDI) would have greater left hemisphere activity in the left executive control network (ECN) at rest.
  
  
  METHODS
  Twenty-five SDI and 25 controls completed a Behavioral Inhibition System/Behavioral Activation System (BIS/BAS) questionnaire and underwent a resting-state fMRI scan. Group independent component analysis was performed. We used template matching to identify the left and right ECN separately and compared the corresponding components across groups. Across group, BAS scores were correlated with signal fluctuations in the left ECN and BIS scores with right ECN.
  
  
  RESULTS
  BAS scores were higher in SDI compared to controls (p<.003) and correlated with signal fluctuation in the left ECN. SDI showed significantly more activity than controls in the left prefrontal cortex of the left ECN. Conversely, SDI showed less activity than controls in the right prefrontal cortex of the right ECN.
  
  
  CONCLUSIONS
  Results from this study suggest that approach tendencies are related to the left ECN, even during rest. Higher resting-state signal in the left ECN may play a role in heightened approach tendencies that contribute to drug-seeking behavior.
authors: Department of Radiology, University of Colorado Denver, CO, United States.
authors: Theodore D
authors: TD
authors: Krmpotich
authors: Jason R
authors: JR
authors: Tregellas
authors: Laetitia L
authors: LL
authors: Thompson
authors: Marie T
authors: MT
authors: Banich
authors: Amanda M
authors: AM
authors: Klenk
authors: Jody L
authors: JL
authors: Tanabe
mesh_terms: D000328:Adult; D056344:Executive Function / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007266:Inhibition, Psychological; D007406:Interview, Psychological; D008279:Magnetic Resonance Imaging; D008297:Male; D009415:Nerve Net / Q000503:physiopathology*; D009483:Neuropsychological Tests; D017397:Prefrontal Cortex / Q000503:physiopathology; D025341:Principal Component Analysis; D012044:Regression Analysis; D019966:Substance-Related Disorders / Q000523:psychology*; D011795:Surveys and Questionnaires