Visual Mismatch Negativity

Abstract

When a deviant tone is presented within a sequence of repetitive (“standard”) tones, it evokes a specific response in the event-related potential (ERP) called mismatch negativity (MMN). This response lasts from about 100 to 250 milliseconds after stimulus onset, is maximal over frontal/central scalp areas, and is thought to originate from temporal and frontal cortices (for reviews, see Naatanen, 1990, 1992, 1995). Naatanen defines the MMN as “the brain’s automatic response to changes in repetitive auditory input” (1990, p. 201). Within the auditory modality, MMN has been observed to changes in tonal frequency, intensity, duration, spatial location, and many other auditory stimuli parameters. An important part of its definition is the automaticity of the response—its independence of attention. Indeed, it has been shown many times that the auditory MMN is unaffected to a large degree by the difficulty (or load) of a concurrent task in the visual modality (Alho et al., 1992; Sams et al., 1985, Ritter et al., 1995). Note that this independence of attention does not imply that the auditory process underlying MMN occur without any attention. An alternative possibility is that the auditory process has its own, modality-specific attentional resource (Wickens, 1984), in which case MMN will be unaffected by the difficulty of a task in a different modality. Indeed, effective withdrawal of auditory attention by a concurrent task in the auditory modality has been shown to reduce the MMN (Alain & Woods, 1997; Woldorff et al., 1991, 1998).