Similarly, covert attention is affected by alcohol, as indicated by the reduced mismatch negativity (MMN) amplitudes for both auditory and visual stimuli (Jaaskelainen et al., 1995, 1996; Kenemans et al., 2010). MMN is an automatic neuronal mismatch between a deviant auditory input and a sensory-memory trace representing the standard stimuli; it is a preattentive process engaging covert attention, and provides an objective measure of auditory discrimination and sensory memory (Näätänen, 1990). (See section on attention – N100 and mismatch negativity, below, for studies on MMN and chronic alcoholics.)
