title: Do tonic and burst TMS modulate the lemniscal and extralemniscal system differentially?
abstract: BACKGROUND
  Tinnitus is an auditory phantom percept related to tonic and burst hyperactivity of the auditory system. Two parallel pathways supply auditory information to the cerebral cortex: the tonotopically organised lemniscal system, and the non-tonotopic extralemniscal system, firing in tonic mode and burst mode respectively. Transcranial magnetic stimulation (TMS) is a non-invasive method capable of modulating activity of the human cortex, by delivering tonic or burst stimuli. Burst stimulation is shown to be more powerful in activating the cerebral cortex than tonic stimulation and bursts may activate neurons that are not activated by tonic stimulations.
  
  
  METHODS
  The effect of both tonic and burst TMS in 14 placebo-negative patients presenting narrow band/white noise tinnitus were analysed.
  
  
  RESULTS
  Our TMS results show that narrow band/white noise tinnitus is better suppressed with burst TMS in comparison to tonic TMS, t(13)=6.4, p=.000. For pure tone tinnitus no difference is found between burst or tonic TMS, t(13)=.3, ns.
  
  
  CONCLUSIONS
  Based on the hypothesis that white noise is the result of hyperactivity in the non-tonotopic system and pure tone tinnitus of the tonotopic system, we suggest that burst stimulation modulates the extralemniscal system and lemniscal system and tonic stimulation only the lemniscal system.
authors.affiliation: Dept of Neurosurgery, ENT, University Hospital Antwerp, Edegem, Belgium. dirk.de.ridder@neurosurgery.be
authors.forename: Dirk
authors.initials: D
authors.lastname: De Ridder
authors.forename: Elsa
authors.initials: E
authors.lastname: van der Loo
authors.forename: Karolien
authors.initials: K
authors.lastname: Van der Kelen
authors.forename: Tomas
authors.initials: T
authors.lastname: Menovsky
authors.forename: Paul
authors.initials: P
authors.lastname: van de Heyning
authors.forename: Aage
authors.initials: A
authors.lastname: Moller
mesh_terms: D000368:Aged; D001303:Auditory Cortex / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D014012:Tinnitus / Q000503:physiopathology / Q000628:therapy*; D050781:Transcranial Magnetic Stimulation / Q000379:methods*