title: Aging influences central motor conduction less than peripheral motor conduction: a transcranial magnetic stimulation study.
abstract: BACKGROUND
  In this study we investigated the effects of aging on corticospinal tract conduction by measuring the corticoconus motor conduction time (CCCT).
  
  
  METHODS
  Motor evoked potentials were recorded from the right tibialis anterior muscle in 100 healthy volunteers. To activate the most proximal part of the cauda equina, magnetic stimulation was performed using a MATS coil over the L1 spinous process (L1-level latency). Transcranial magnetic stimulation of the motor cortex was also conducted (cortical latency). To obtain the CCCT, the L1-level latency was subtracted from the cortical latency.
  
  
  RESULTS
  Age was significantly correlated with L1-level latency, but it was not significantly correlated with CCCT.
  
  
  CONCLUSIONS
  CCCT is the most direct indicator of corticospinal tract conduction, whereas L1-level latency reflects whole peripheral motor conduction. Central motor conduction was found to be relatively less affected by aging compared with peripheral motor conduction.
authors.affiliation: Department of Neurology, Japanese Red Cross Medical Center, 4-1-22 Hiroo, Shibuya-ku, Tokyo 150-8935, Japan. hideyukimatsumoto.jp@gmail.com
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Matsumoto
authors.forename: Yuko
authors.initials: Y
authors.lastname: Konoma
authors.forename: Takahiro
authors.initials: T
authors.lastname: Shimizu
authors.forename: Shingo
authors.initials: S
authors.lastname: Okabe
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Shirota
authors.forename: Ritsuko
authors.initials: R
authors.lastname: Hanajima
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Terao
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Ugawa
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D001703:Biophysics; D002420:Cauda Equina / Q000502:physiology; D002490:Central Nervous System / Q000502:physiology*; D019054:Evoked Potentials, Motor / Q000276:immunology* / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009431:Neural Conduction / Q000502:physiology*; D010525:Peripheral Nerves / Q000502:physiology*; D011712:Pyramidal Tracts / Q000502:physiology; D011930:Reaction Time; D050781:Transcranial Magnetic Stimulation; D055815:Young Adult