title: Reduced cerebral cortex inhibition in dystonia: direct evidence in humans.
abstract: OBJECTIVE
  A loss of inhibition in central motor circuits resulting in abnormal motor control is the hypothesised cause of dystonia. So far, changes in inhibitory function of cerebral cortex in dystonia, have been revealed only indirectly by recording muscle responses evoked by transcranial magnetic stimulation (TMS) of the brain. The aim of present study was to evaluate more directly cerebral cortex changes in dystonia. We had the almost unique opportunity to record directly motor cortex output after brain stimulation, in a dystonic patient who had epidural electrodes implanted in the upper cervical cord.
  
  
  METHODS
  We evaluated descending activity evoked by single and paired pulse TMS together with the inhibitory effects produced by afferent stimuli on TMS evoked activity, and compared the results with those obtained in thirteen subjects with no central nervous system abnormality who also had cervical spinal electrodes.
  
  
  RESULTS
  The intrinsic inhibitory activity produced by paired TMS of the motor cortex, and the inhibitory effects produced by afferent inputs, were suppressed in the patient with dystonia.
  
  
  CONCLUSIONS
  These findings provide a direct evidence of the abnormality in motor cortex inhibitory systems in dystonia.
  
  
  CONCLUSIONS
  The abnormality in cortical inhibitory system might have a role in the pathophysiology of dystonia.
authors.affiliation: Institute of Neurology, Università Cattolica, L.go A. Gemelli 8, 00168 Rome, Italy. vdilazzaro@rm.unicatt.it
authors.forename: V
authors.initials: V
authors.lastname: Di Lazzaro
authors.forename: A
authors.initials: A
authors.lastname: Oliviero
authors.forename: P
authors.initials: P
authors.lastname: Profice
authors.forename: M
authors.initials: M
authors.lastname: Dileone
authors.forename: F
authors.initials: F
authors.lastname: Pilato
authors.forename: A
authors.initials: A
authors.lastname: Insola
authors.forename: G
authors.initials: G
authors.lastname: Della Marca
authors.forename: P A
authors.initials: PA
authors.lastname: Tonali
authors.forename: P
authors.initials: P
authors.lastname: Mazzone
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D001703:Biophysics; D002540:Cerebral Cortex / Q000503:physiopathology*; D004421:Dystonia / Q000473:pathology* / Q000503:physiopathology*; D004569:Electroencephalography; D019054:Evoked Potentials, Motor / Q000502:physiology; D005260:Female; D006801:Humans; D008875:Middle Aged; D009433:Neural Inhibition / Q000502:physiology*; D011712:Pyramidal Tracts / Q000503:physiopathology; D011930:Reaction Time / Q000502:physiology; D012684:Sensory Thresholds; D050781:Transcranial Magnetic Stimulation