The effect of stimulus probability on the somatosensory mismatch field

Kosuke Akatsuka*, Toshiaki Wasaka, Hiroki Nakata, Tetsuo Kida, Ryusuke Kakigi

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

37 Citations (Scopus)


We investigated the effect of deviant stimulus probability on the somatosensory magnetic mismatch negativity (MMNm) using an electrical two-point stimulation. First, we determined the discrimination threshold (DT) of the two-point distance. We applied standard stimuli at a distance that subjects felt as one point and deviant stimuli at a distance that subjects definitely felt as two points. We used three deviant stimulus probabilities, 10, 30, and 50%. The components peaking around 30-70 ms (first component) and 150-250 ms (fourth component) following deviant stimuli were significantly larger than those following standard stimuli in 10% condition, but not in 30 or 50% condition. The equivalent current dipole (ECD) was located in the contralateral primary somatosensory cortex (cSI) for the first component, and in the cSI and in the contralateral secondary somatosensory cortex (cSII) for the fourth component. The peak amplitude of the MMNm decreased as the probability of the deviant stimulus increased. The Somatosensory MMNm was affected by deviant stimulus probability similar to an auditory mismatch negativity (MMN).

Original languageEnglish
Pages (from-to)607-614
Number of pages8
JournalExperimental Brain Research
Issue number4
Publication statusPublished - 2007 Aug


  • Magnetic mismatch negativity
  • Magnetoencephalography
  • Mismatch negativity
  • Somatosensory
  • Stimulus probability

ASJC Scopus subject areas

  • Neuroscience(all)


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