Priming Deficiency in Male Subjects at Risk for Alcoholism: The N4 During a Lexical Decision Task

Background:  While there is extensive literature on the relationship between the P3 component of event-related potentials (ERPs) and risk for alcoholism, there are few published studies regarding other potentially important ERP components. One important candidate is the N4(00) component in the context of semantic processing, as abnormalities in this component have been reported for adult alcoholics.
Method:  A semantic priming task was administered to nonalcohol dependent male offspring (18 to 25 years) of alcoholic fathers [high risk (HR) n  = 23] and nonalcoholic fathers [low risk (LR) n  = 28] to study whether the 2 groups differ in terms of the N4 component. Subjects were presented with 150 words and 150 nonwords. Among the words, 50 words (primed) were preceded by their antonyms (prime, n  = 50), whereas the remaining 50 words were unprimed. For the analysis, N4 amplitude and latency as well as behavioral measures for the primed and unprimed words were considered.
Results:  A significant interaction effect was observed between semantic condition and group, where HR subjects did not show N4 attenuation for primed stimuli.
Conclusion:  The lack of N4 attenuation to primed stimuli and/or inability to differentiate between primed and unprimed stimuli, without latency and reaction time being affected, suggest deficits in semantic priming, especially in semantic expectancy and/or postlexical semantic processing in HR male offspring. Further, it indicates that it might be an electrophysiological endophenotype that reflects genetic vulnerability to develop alcoholism.