Event-related correlates of response suppression as indicators of novelty seeking in alcoholics

Abstract

Novelty Seeking including impulsive behaviour is a personality dimension which has been shown to be related to early-onset alcoholism and to high relapse rates. The cued Continuous performance Test (CPT) is an experimental paradigm for active response control requiring a choice reaction between execution (Go) and inhibition (NoGo) of a prepared motor response. Metabolic functional methods have shown right frontal brain activation throughout the period of a CPT, and the spatial analysis of the associated event-related brain electrical (ERP) field potentials revealed that this right frontal activation was due to the NoGo subset of the task. The ERP fields allow distinction between the Go and NoGo conditions with one spatial parameter (NoGo-anteriorization) in single cases, and the magnitude of this parameter is thought to be related to inhibitory frontal lobe control. Twenty patients with severe alcohol dependence and 20 age- and sex-matched healthy controls were included in the study and investigated with a 21-channel electroencephalogram while performing a cued CPT. Consistent with previous studies, NoGo-anteriorization was present in every case in both groups. The ERP field differed between alcoholics and controls in the Go condition (P < 0.05) and NoGo-anteriorization in alcoholics was correlated inversely with Novelty Seeking in Cloninger's Temperament and Character inventory (r = 0.67, P < 0.01). This indicates a reduced frontal lobe contribution during response control in alcoholics with impulsive behaviour and identifies a possible biological marker for the clinical evaluation of the risk of relapse in alcoholism.