title: Intensity-dependent effects of 1 Hz rTMS on human corticospinal excitability.
abstract: OBJECTIVE
  This study explored whether the effects of repetitive transcranial magnetic stimulation (rTMS) on corticospinal excitability are dependent on the stimulation intensity and examined the effect of rTMS on inhibitory function.
  
  
  METHODS
  Nine normal volunteers received 15min of 1Hz rTMS at 85 and 115% of the resting motor threshold (RMT). Cortical excitability was measured before and after rTMS.
  
  
  RESULTS
  rTMS at both intensities produced an increase in the RMT but only 115% stimulation reduced the size of motor evoked potentials (MEPs). rTMS had no effects on the cortical silent period or cortical inhibition measured with paired pulse TMS.
  
  
  CONCLUSIONS
  The effects of 1Hz rTMS on motor cortex excitability are partially dependent on stimulus intensity and the effects of rTMS on motor thresholds and MEP size may differ.
authors.affiliation: Department of Psychological Medicine, Dandenong Psychiatry Research Centre, Monash University, P.O. Box 956, Victoria 3175, Australia. paul.fitzgerald@med.monash.edu.au
authors.forename: Paul B
authors.initials: PB
authors.lastname: Fitzgerald
authors.forename: Timothy L
authors.initials: TL
authors.lastname: Brown
authors.forename: Z Jeff
authors.initials: ZJ
authors.lastname: Daskalakis
authors.forename: Robert
authors.initials: R
authors.lastname: Chen
authors.forename: J
authors.initials: J
authors.lastname: Kulkarni
mesh_terms: D000328:Adult; D002540:Cerebral Cortex / Q000502:physiology*; D004307:Dose-Response Relationship, Radiation; D004569:Electroencephalography; D004574:Electromagnetic Fields; D004576:Electromyography; D019054:Evoked Potentials, Motor / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D013116:Spinal Cord / Q000502:physiology*