title: Does electroencephalogram phase variability account for reduced P3 brain potential in externalizing disorders?
abstract: OBJECTIVE
  Amplitude deficits of the P3 event-related potential (ERP) are associated with externalizing psychopathology but little is known about the nature of underlying brain electrical activity that accounts for this amplitude reduction. We sought to understand if group differences in task-induced phase-locking in electroencephalographic (EEG) delta and theta frequencies may account for P3-externalizing associations.
  
  
  METHODS
  Adult males (N=410) completed a visual oddball task and frontal and parietal P3-related delta- and theta-band phase-invariant evoked energy and inter-trial phase-locking measures were investigated with respect to the externalizing spectrum, including substance dependence, adult antisociality, and childhood disruptive disorders. We hypothesized that P3-related phase-locking is weaker in externalizing-diagnosed individuals and this might mediate prior findings of reduced evoked P3 energy.
  
  
  RESULTS
  Reductions in both evoked energy and phase-locking, in both frequency bands, at both scalp sites, were associated with greater odds of externalizing diagnoses. Generally, adding phase-locking to evoked energy came with better prediction model fit. Moreover, reduced theta-band phase-locking partially mediated the effects of within-frequency evoked energy on externalizing prediction.
  
  
  CONCLUSIONS
  Inter-trial phase-locking underlying P3 appears to be an important distinction between externalizing and control subjects.
  
  
  CONCLUSIONS
  This cross-trial phase-variability for externalizing-diagnosed individuals might reflect deficient top-down "tuning" by neuromodulatory systems.
authors.affiliation: University of Minnesota, Twin Cities, USA. Electronic address: burwell@umn.edu.
authors.forename: Scott J
authors.initials: SJ
authors.lastname: Burwell
authors.affiliation: University of Minnesota, Twin Cities, USA.
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Malone
authors.affiliation: University of Maryland, College Park, USA.
authors.forename: Edward M
authors.initials: EM
authors.lastname: Bernat
authors.affiliation: University of Minnesota, Twin Cities, USA.
authors.forename: William G
authors.initials: WG
authors.lastname: Iacono
mesh_terms: D000328:Adult; D002540:Cerebral Cortex / Q000503:physiopathology*; D015331:Cohort Studies; D003700:Delta Rhythm / Q000502:physiology*; D004200:Diseases in Twins / Q000175:diagnosis / Q000503:physiopathology; D018913:Event-Related Potentials, P300 / Q000502:physiology*; D006801:Humans; D008297:Male; D001523:Mental Disorders / Q000175:diagnosis / Q000503:physiopathology*; D013826:Theta Rhythm / Q000502:physiology*
keywords: Event-related potential; Externalizing; P3; Phase-locking; Substance use; Theta