title: Parieto-motor cortical dysfunction in primary cervical dystonia.
abstract: BACKGROUND
  Dystonia is considered as a motor network disorder involving the dysfunction of the posterior parietal cortex, a region involved in preparing and executing reaching movements.
  
  
  OBJECTIVE
  We used transcranial magnetic stimulation to test the hypothesis that cervical dystonic patients may have a disrupted parieto-motor connectivity.
  
  
  METHODS
  We enrolled 14 patients with primary cervical dystonia and 14 controls. A paired-pulse transcranial magnetic stimulation protocol was applied over the right posterior parietal cortex and the right primary motor area. Changes in the amplitudes of motor evoked potential were analyzed as an index of parieto-motor effective connectivity. Patients and healthy subjects were also evaluated with a reaching task. Reaction and movement times were measured.
  
  
  RESULTS
  In healthy subjects, but not in dystonic patients, there was a facilitation of motor evoked potential amplitudes when the conditioning parietal stimulus preceded the test stimulus applied over the primary motor area by 4 ms. Reaction and movement times were significantly slower in patients than in controls. In dystonic patients, the relative strength of parieto-motor connectivity correlated with movement times.
  
  
  CONCLUSIONS
  Parieto-motor cortical connectivity is impaired in cervical dystonic patients. This neurophysiological trait is associated with slower reaching movements.
authors.affiliation: Unidad de Trastornos del Movimiento, Servicio de Neurología y Neurofisiología, Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.
authors.forename: Paolo
authors.initials: P
authors.lastname: Porcacchia
authors.affiliation: Unidad de Trastornos del Movimiento, Servicio de Neurología y Neurofisiología, Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Spain.
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Palomar
authors.affiliation: Unidad de Trastornos del Movimiento, Servicio de Neurología y Neurofisiología, Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.
authors.forename: María T
authors.initials: MT
authors.lastname: Cáceres-Redondo
authors.affiliation: Unidad de Trastornos del Movimiento, Servicio de Neurología y Neurofisiología, Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.
authors.forename: Ismael
authors.initials: I
authors.lastname: Huertas-Fernández
authors.affiliation: Unidad de Trastornos del Movimiento, Servicio de Neurología y Neurofisiología, Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.
authors.forename: Juan F
authors.initials: JF
authors.lastname: Martín-Rodríguez
authors.affiliation: Unidad de Trastornos del Movimiento, Servicio de Neurología y Neurofisiología, Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.
authors.forename: Fátima
authors.initials: F
authors.lastname: Carrillo
authors.affiliation: Stroke Unit, Dipartimento di Neuroscienze, Università di Roma Tor Vergata, Rome, Italy; Laboratorio di Neurologia Clinica e Comportamentale, Fondazione S. Lucia I.R.C.C.S., Rome, Italy.
authors.forename: Giacomo
authors.initials: G
authors.lastname: Koch
authors.affiliation: Unidad de Trastornos del Movimiento, Servicio de Neurología y Neurofisiología, Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Spain. Electronic address: pmir@us.es.
authors.forename: Pablo
authors.initials: P
authors.lastname: Mir
mesh_terms: D000328:Adult; D000368:Aged; D004421:Dystonia / Q000151:congenital; D019054:Evoked Potentials, Motor; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000503:physiopathology*; D010296:Parietal Lobe / Q000503:physiopathology*; D011930:Reaction Time; D014103:Torticollis / Q000151:congenital* / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy; D050781:Transcranial Magnetic Stimulation / Q000379:methods*
keywords: Dystonia; Hypokinesia; Parietal lobe; Transcranial magnetic stimulation