title: Reduced frontal lobe activity in subjects with high impulsivity and alcoholism.
abstract: OBJECTIVE
  Impulsivity is an important characteristic of many psychiatric disorders, including substance-related disorders. These disinhibitory disorders have a similar underlying genetic diathesis, with each disorder representing a different expression of the same underlying genetic liability. This study assessed whether there is a relationship between impulsivity and alcohol dependence, and their correlations with P3 (P300) amplitude, a proposed endophenotype of alcoholism.
  
  
  METHODS
  Healthy control subjects (n=58) and subjects with DSM-IV diagnosis of alcohol dependence (n=57) were assessed with a visual oddball task. Event-Related Potentials (ERPs) were recorded from 61 scalp electrodes and P3 amplitudes measured. Barratt Impulsiveness Scale (BIS), version 11, was used to evaluate impulsivity. Source localization of P3 was computed using low-resolution brain electromagnetic tomography (LORETA).
  
  
  RESULTS
  Alcoholic subjects manifested reductions in target P3 amplitudes (p<0.0001). Using LORETA, significantly reduced activation was mapped in the cingulate, medial, and superior frontal regions in alcoholic subjects and highly impulsive subjects. Alcoholic subjects had significantly higher scores on the BIS (p<0.0001) than nonalcoholic individuals. There were significant negative correlations between total scores on BIS and P3 amplitude (r=-0.274, p=0.003, on Pz; r=-0.250, p=0.007, on Cz).
  
  
  CONCLUSIONS
  Our results demonstrate a strong frontal focus of reduced activation during processing of visual targets in alcoholic subjects and individuals with higher impulsivity. The findings suggest that impulsivity may be an important factor that underlies the pathogenesis of alcohol dependence. Studies are underway to examine the relationship between impulsivity and ERPs in offspring of alcoholic subjects, and to identify genes associated with the underlying predisposition involved in disinhibitory disorders.
authors.affiliation: Henri Begleiter Neurodynamics Laboratory, Department of Psychiatry, SUNY Downstate Medical Center, 450 Clarkson Avenue, Brooklyn, NY 11203, USA.
authors.forename: Andrew C H
authors.initials: AC
authors.lastname: Chen
authors.forename: Bernice
authors.initials: B
authors.lastname: Porjesz
authors.forename: Madhavi
authors.initials: M
authors.lastname: Rangaswamy
authors.forename: Chella
authors.initials: C
authors.lastname: Kamarajan
authors.forename: Yongqiang
authors.initials: Y
authors.lastname: Tang
authors.forename: Kevin A
authors.initials: KA
authors.lastname: Jones
authors.forename: David B
authors.initials: DB
authors.lastname: Chorlian
authors.forename: Arthur T
authors.initials: AT
authors.lastname: Stimus
authors.forename: Henri
authors.initials: H
authors.lastname: Begleiter
mesh_terms: D000328:Adult; D000437:Alcoholism / Q000503:physiopathology* / Q000523:psychology; D003627:Data Interpretation, Statistical; D004569:Electroencephalography; D005071:Evoked Potentials / Q000502:physiology; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology*; D006801:Humans; D007175:Impulsive Behavior / Q000503:physiopathology* / Q000523:psychology; D008297:Male; D011569:Psychiatric Status Rating Scales; D012815:Signal Processing, Computer-Assisted; D014796:Visual Perception / Q000502:physiology