title: Impulsivity and risk-taking behavior in focal frontal lobe lesions.
abstract: Frontal lobe dysfunction may underlie excessively impulsive and risky behavior observed in a range of neurological disorders. We devised a gambling task to examine these behavior tendencies in a sample of patients who had sustained focal damage to the frontal lobes or nonfrontal cortical regions as well as in a matched sample of healthy control subjects. The main objectives of the study were: (1) to behaviorally dissociate impulsivity and risk-taking; (2) to examine potential associations between specific frontal lesion sites and impulsivity or risk-taking; (3) to investigate the influence of reinforcement and trial timing on both behaviors. Our results indicated that patients and controls were equally likely to perform impulsively. Risk-taking performance strategies, however, were related to left ventrolateral and orbital lesion sites. Moreover, risk-taking was also associated with blunted response alteration following a nonrewarded trial. Patients and control subjects showed identical responses to reward-timing manipulations consistent with formal decision-making theory. These findings suggest that ventrolateral and orbital lesions are related to the reward-based aspects of decision-making (risk-taking) rather than to simple response disinhibition (impulsivity). Reduced reaction to the negative consequences of one's actions may underlie this behavior pattern.
authors.affiliation: Rotman Research Institute, Baycrest, Toronto, Ontario, Canada.
authors.forename: D
authors.initials: D
authors.lastname: Floden
authors.forename: M P
authors.initials: MP
authors.lastname: Alexander
authors.forename: C S
authors.initials: CS
authors.lastname: Kubu
authors.forename: D
authors.initials: D
authors.lastname: Katz
authors.forename: D T
authors.initials: DT
authors.lastname: Stuss
mesh_terms: D000328:Adult; D001930:Brain Injuries / Q000150:complications / Q000473:pathology / Q000523:psychology; D001931:Brain Mapping; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology*; D006801:Humans; D007175:Impulsive Behavior / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D012201:Reward; D012309:Risk-Taking; D012720:Severity of Illness Index; D013997:Time Factors