title: Transcranial magnetic stimulation of the central and peripheral motor pathways to the lingual muscles in cats.
abstract: OBJECTIVE
  We have assessed a technique to stimulate the intracranial hypoglossal nerve with ease and reproducibility by using magnetic coils (MCs) and to detect a reliable site of excitation in animal experiments in order to establish a method to evaluate the motor pathway to lingual muscles.
  
  
  METHODS
  We recorded the motor responses from the lingual muscles of 5 adult cats under general anesthesia by magnetic and electrical stimulation of the intracranial hypoglossal nerves. Figure of 8 and round MCs were used to investigate the optimal position and direction to evoke the motor responses.
  
  
  RESULTS
  The round MC was useful for cortical stimulation. The figure of 8 coil, positioned in the back of the head of the examined side, parallel to the cervical spine, was essential for stimulation of the intracranial hypoglossal nerve. Analysis of the latencies, and the observation that the motor responses disappeared after transection of the nerves at the exit of the hypoglossal canal, demonstrated that the site of the excitation is at the exit of the hypoglossal canal.
  
  
  CONCLUSIONS
  Magnetic stimulation using a figure of 8 coil can elicit tongue motor responses with ease and reliable reproducibility, stimulating the hypoglossal nerve at the exit of the hypoglossal canal.
authors.affiliation: Department of Neurosurgery, Keio University School of Medicine, Tokyo, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Kobayashi
authors.forename: T
authors.initials: T
authors.lastname: Ohira
authors.forename: M
authors.initials: M
authors.lastname: Ochiai
authors.forename: B
authors.initials: B
authors.lastname: Mihara
authors.forename: T
authors.initials: T
authors.lastname: Kawase
mesh_terms: D000818:Animals; D002415:Cats; D019054:Evoked Potentials, Motor / Q000502:physiology*; D009132:Muscles / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D014059:Tongue / Q000502:physiology*; D050781:Transcranial Magnetic Stimulation