title: Effects of high frequency repetitive transcranial magnetic stimulation on P(300) event-related potentials.
abstract: OBJECTIVE
  Auditory event-related potentials (P(300)-ERPs) were analyzed before and after repetitive transcranial magnetic stimulation (rTMS).
  
  
  METHODS
  Two rTMS trains (10 Hz, 3 s, 100% motor threshold and 5 min interval) were delivered over the left frontal area in healthy subjects. P(300)-ERPs were recorded at 14 electrode sites on the scalp using a typical oddball paradigm before and after rTMS. The latencies and amplitudes of N(100), P(200), N(200) and P(300) were measured and compared. The directed coherence (DCOH) was estimated to demonstrate information flow between different cortical areas.
  
  
  RESULTS
  rTMS significantly influenced P(300)-ERPs. The effects differed on the different components (P<0.001). The latency of P(300) significantly increased after stimulation, which was more obvious in the frontal and central areas. The changes in P(300) amplitude were not significant (P>0.05). The DCOH from the frontal, central, parietal and occipital areas to the temporal area was significantly higher than the DCOH from the temporal area to the former 4 areas (P<0.01).
  
  
  CONCLUSIONS
  rTMS with the present parameters can affect P(300)-ERPs, leading to a delayed P(300) component and changes in information connections around the stimulated site. Our data suggest that rTMS may postpone neuronal activities related to cognitive processing.
authors.affiliation: Department of Neuropsychiatry, Faculty of Medicine, Kagoshima University, 8-35-1 Sakuragaoka, 890-8520, Kagoshima City, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Jing
authors.forename: M
authors.initials: M
authors.lastname: Takigawa
authors.forename: K
authors.initials: K
authors.lastname: Hamada
authors.forename: H
authors.initials: H
authors.lastname: Okamura
authors.forename: Y
authors.initials: Y
authors.lastname: Kawaika
authors.forename: T
authors.initials: T
authors.lastname: Yonezawa
authors.forename: H
authors.initials: H
authors.lastname: Fukuzako
mesh_terms: D000328:Adult; D001921:Brain / Q000502:physiology*; D018913:Event-Related Potentials, P300 / Q000502:physiology*; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D006801:Humans; D008297:Male; D010812:Physical Stimulation / Q000379:methods; D011930:Reaction Time / Q000502:physiology; D050781:Transcranial Magnetic Stimulation