title: Bidirectional neural connectivity between basal temporal and posterior language areas in humans.
abstract: OBJECTIVE
  The basal temporal language area (BTL) is known to be involved in the semantic processing of language. To investigate the neural connectivity between BTL and the posterior language area (PL), we used cortico-cortical evoked potential (CCEP) technique.
  
  
  METHODS
  Four patients with intractable epilepsy who underwent presurgical evaluation with subdural electrodes were examined. All patients were right-handed and left language dominance by Wada test. We directly stimulated 20 pairs of electrodes placed on BTL in patient 1-3, putative BTL in patient 4, and PL in patient 1-4. In patient 4, all electrodes on the left temporal basal area were stimulated.
  
  
  RESULTS
  We could record 132 CCEP responses including 40 responses by the left basal temporal stimulation in patient 4. The waveforms from PL to BTL were triphasic, while those from BTL to PL were biphasic. The mean latency of the first negative peak (N1) was shorter at BTL (31.8-41.0ms; mean 35.1ms) than at PL (39.6-73.2ms; mean 52.3ms).
  
  
  CONCLUSIONS
  We revealed the uneven bidirectional connection between BTL and PL.
  
  
  CONCLUSIONS
  We speculated that the two language areas are connected mainly through subcortical fibers from PL to BTL and through cortico-cortical fibers from BTL to PL, mediated by multisynaptic transmissions.
authors.affiliation: Department of Neurology, National Epilepsy Center, Shizuoka Institute of Epilepsy and Neurological Disorders, Japan.
authors.forename: Kunihiko
authors.initials: K
authors.lastname: Araki
authors.affiliation: Department of Neurology, National Epilepsy Center, Shizuoka Institute of Epilepsy and Neurological Disorders, Japan. Electronic address: kyht-terada@umin.net.
authors.forename: Kiyohito
authors.initials: K
authors.lastname: Terada
authors.affiliation: Department of Neurology, National Epilepsy Center, Shizuoka Institute of Epilepsy and Neurological Disorders, Japan.
authors.forename: Keiko
authors.initials: K
authors.lastname: Usui
authors.affiliation: Department of Neurosurgery, National Epilepsy Center, Shizuoka Institute of Epilepsy and Neurological Disorders, Japan.
authors.forename: Naotaka
authors.initials: N
authors.lastname: Usui
authors.affiliation: Department of Neurology, National Epilepsy Center, Shizuoka Institute of Epilepsy and Neurological Disorders, Japan.
authors.forename: Yasukiyo
authors.initials: Y
authors.lastname: Araki
authors.affiliation: Department of Neurosurgery, National Epilepsy Center, Shizuoka Institute of Epilepsy and Neurological Disorders, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Baba
authors.affiliation: Department of Neurosurgery, National Epilepsy Center, Shizuoka Institute of Epilepsy and Neurological Disorders, Japan.
authors.forename: Kazumi
authors.initials: K
authors.lastname: Matsuda
authors.affiliation: Department of Neurosurgery, National Epilepsy Center, Shizuoka Institute of Epilepsy and Neurological Disorders, Japan.
authors.forename: Takayasu
authors.initials: T
authors.lastname: Tottori
authors.affiliation: Department of Psychiatry, National Epilepsy Center, Shizuoka Institute of Epilepsy and Neurological Disorders, Japan.
authors.forename: Yushi
authors.initials: Y
authors.lastname: Inoue
mesh_terms: D000293:Adolescent; D000328:Adult; D001931:Brain Mapping / Q000379:methods*; D004558:Electric Stimulation / Q000379:methods; D004567:Electrodes, Implanted; D004827:Epilepsy / Q000175:diagnosis / Q000503:physiopathology; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D006801:Humans; D007802:Language; D008297:Male; D008875:Middle Aged; D009415:Nerve Net / Q000502:physiology*; D013702:Temporal Lobe / Q000502:physiology*; D055815:Young Adult
keywords: Basal temporal language area; Cortico-cortical evoked potential; Language system; Posterior language area