MISMATCH NEGATIVITY SUBCOMPONENTS AND ETHYL-ALCOHOL

Effects of ethanol (0.55 and 0.85 g/kg) on event-related potentials we re investigated by presenting 50-ms standard and 25-ms deviant pure to nes to 9 social drinkers during a reading task, in a single-blind, pla cebo-controlled paradigm. Whereas the lower ethanol dose had no impact on ERPs with an 0.8-s inter-stimulus interval (ISI), it attenuated th e N1, P2, and mismatch negativity (MMN) amplitudes with a longer ISI o f 2.4 s. The higher alcohol dose increased the N1 peak latency with bo th ISIs. It also suppressed the N1 and MMN amplitudes with the longer ISI, The MMN suppression did not, however, occur at scalp sites below the Sylvian fissure, thus suggesting that ethanol affected only the fr ontal MMN subgenerator. Moreover, the different dose responses of the N1, P2, and MMN (subcomponents) to ethanol may indicate that the neuro transmitter systems underlying their generation are, to some extent, d ifferent.