title: Cross-modal symbolic processing can elicit either an N2 or a protracted N2/N400 response.
abstract: A cross-modal symbolic paradigm was used to elicit EEG activity related to semantic incongruence. Twenty-five undergraduate students viewed pairings of visual lexical cues (e.g., DOG) with congruent (50% of trials) or incongruent (50%) auditory nonlexical stimuli (animal vocalizations; e.g., sound of a dog woofing or a cat meowing). In one condition, many different pairs of congruent/incongruent stimuli were shown, whereas in a second condition only two pairs of stimuli were repeatedly shown. A typical N400-like pattern of incongruence-related activity (including activity in the N2 time window) was evident in the condition using many stimuli, whereas the incongruence-related activity in the two-stimuli condition was confined to differential N2-like activity. A supplementary analysis excluded stimulus characteristics as the source of this differential activity between conditions. We found that a single individual performing a fixed task can demonstrate either a protracted N400-like pattern of activity or a more temporally focused N2-like pattern of activity in response to the same stimulus, which suggests that the N2 may be a precursor to the protracted N400 response.
authors.affiliation: School of Psychology, UNSW Australia, Sydney, Australia.
authors.forename: Oren
authors.identifier: 0000-0002-9833-9998
authors.initials: O
authors.lastname: Griffiths
authors.affiliation: School of Psychology, UNSW Australia, Sydney, Australia.
authors.forename: Mike E
authors.initials: ME
authors.lastname: Le Pelley
authors.affiliation: School of Psychology, UNSW Australia, Sydney, Australia.
authors.forename: Bradley N
authors.initials: BN
authors.lastname: Jack
authors.affiliation: School of Psychology, UNSW Australia, Sydney, Australia.
authors.forename: David
authors.initials: D
authors.lastname: Luque
authors.affiliation: School of Psychology, UNSW Australia, Sydney, Australia.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Whitford
mesh_terms: D000161:Acoustic Stimulation; D000293:Adolescent; D000328:Adult; D001307:Auditory Perception / Q000502:physiology*; D002540:Cerebral Cortex / Q000502:physiology*; D004569:Electroencephalography; D005071:Evoked Potentials; D006801:Humans; D010775:Photic Stimulation; D012660:Semantics; D014796:Visual Perception / Q000502:physiology*; D055815:Young Adult
keywords: EEG; ERPs; N2; N400; Semantic memory