title: Electrophysiological (EEG) evidence for reduced performance monitoring in euthymic bipolar disorder.
abstract: OBJECTIVE
  Apart from mood episodes, many cognitive deficits are present in bipolar disorder (BD). Performance monitoring is an important aspect of executive functioning and involves continuous monitoring of behavior and making subsequent changes when an error is made. On a neurophysiological level, the error-related negativity (ERN), an event-related brain potential (ERP) generated in the anterior cingulate cortex (ACC), reflects this process of performance monitoring. Abnormal ERN amplitudes have been observed in many major psychiatric disorders. However, despite conflicting evidence regarding the role of the ACC in BD, no studies to date have investigated performance monitoring as reflected in the ERN in BD.
  
  
  METHODS
  Sixteen patients with BD in a euthymic state and 14 matched healthy controls performed a speeded two-choice reaction-time paradigm (Flankers Task) while electroencephalogram (EEG) measures were obtained. Behavioral and ERP measurements were analyzed for the two groups.
  
  
  RESULTS
  The patients with BD, although euthymic, scored higher on depressive symptoms than healthy controls. While no behavioral group differences were found, patients with BD displayed lower ERN amplitudes than healthy controls when controlling for effects of residual mood.
  
  
  CONCLUSIONS
  The lower ERN amplitudes in the BD group reflect reduced performance monitoring and extend current knowledge of executive functioning in BD. Importantly, these findings go a long way to resolving the contradictory results regarding ACC involvement in BD by showing that taking into account residual mood may greatly influence error-related ACC activations and is critically important in understanding cognitive deficits in BD.
authors.affiliation: Collaborative Antwerp Psychiatric Research Institute (CAPRI), University of Antwerp, Antwerp.
authors.forename: Anne M
authors.initials: AM
authors.lastname: Morsel
authors.forename: Manuel
authors.initials: M
authors.lastname: Morrens
authors.forename: Anke
authors.initials: A
authors.lastname: Temmerman
authors.forename: Bernard
authors.initials: B
authors.lastname: Sabbe
authors.forename: Ellen R A
authors.initials: ER
authors.lastname: de Bruijn
mesh_terms: D000328:Adult; D001714:Bipolar Disorder / Q000150:complications*; D016022:Case-Control Studies; D002755:Choice Behavior / Q000502:physiology; D003072:Cognition Disorders / Q000175:diagnosis* / Q000209:etiology*; D004569:Electroencephalography; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D006179:Gyrus Cinguli / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D011597:Psychomotor Performance; D011930:Reaction Time / Q000502:physiology*
keywords: ERN; anterior cingulate cortex; bipolar disorder; error-related negativity; performance monitoring