title: Visual mismatch response evoked by a perceptually indistinguishable oddball.
abstract: Mismatch field (MMF) is an early magnetoencephalographic response evoked by deviant stimuli within a sequence of standard stimuli. Although auditory MMF is reported to be an automatic response, the automaticity of visual MMF has not been clearly demonstrated, partly because of the difficulty in designing an ignore condition. Our modified oddball paradigm had a masking stimulus inserted between briefly presented standard and deviant stimuli (vertical gratings with different spatial frequencies). Perceptual discrimination between masked standard and deviant stimuli was difficult, but the early magnetoencephalographic response for the deviant was significantly larger than that for the standard, when the former had a higher spatial frequency than the latter. Our findings strongly support the hypothesis that visual MMF is evoked automatically.
authors.affiliation: Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561, Japan. kogai@brain.k.u-tokyo.ac.jp
authors.forename: Takayoshi
authors.initials: T
authors.lastname: Kogai
authors.forename: Atsushi
authors.initials: A
authors.lastname: Aoyama
authors.forename: Kaoru
authors.initials: K
authors.lastname: Amano
authors.forename: Tsunehiro
authors.initials: T
authors.lastname: Takeda
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D001921:Brain / Q000033:anatomy & histology / Q000502:physiology; D003627:Data Interpretation, Statistical; D004192:Discrimination, Psychological / Q000502:physiology; D005072:Evoked Potentials, Auditory / Q000502:physiology; D005074:Evoked Potentials, Visual / Q000502:physiology; D005403:Fixation, Ocular; D006801:Humans; D015225:Magnetoencephalography; D008297:Male; D010470:Perceptual Masking / Q000502:physiology; D010775:Photic Stimulation; D011597:Psychomotor Performance / Q000502:physiology; D011930:Reaction Time / Q000502:physiology; D014794:Visual Fields / Q000502:physiology; D014796:Visual Perception / Q000502:physiology*; D055815:Young Adult