title: Abnormal motor cortex plasticity in juvenile myoclonic epilepsy.
abstract: OBJECTIVE
  Abnormal cortical plasticity has been hypothesized to play a crucial role in the pathogenesis of juvenile myoclonic epilepsy (JME). To study the motor cortical plasticity we used paired associative stimulation (PAS). When a repetitive electrical stimulus to the median nerve is paired with a transcranial magnetic stimulus (TMS) pulse over the controlateral motor cortex with at an interstimulus interval (ISI) of 21.5-25ms, a long term potentiation (LTP)-like synaptic plasticity is induced in the corticospinal system. Aim of this study was to investigate the motor cortex LTP-like synaptic plasticity by means of PAS in patients with JME.
  
  
  METHODS
  Twelve adult patients with JME were compared with 13 healthy subjects of similar age and sex. PAS consisted of 180 electrical stimuli of the right median nerve paired with a single TMS over the hotspot of right abductor pollicis brevis (APB) at an ISI of 25ms (PAS25). We measured motor evoked potentials (MEPs) before and after each intervention for up to 30min.
  
  
  RESULTS
  In healthy subjects the PAS25 protocol was followed by a significant increase of the MEP amplitude (p<0.001). On the contrary, in patients with JME, the MEP amplitude did not change.
  
  
  CONCLUSIONS
  Defective motor cortex plasticity is likely involved in the pathogenesis of JME.
authors.affiliation: Department of Translational Medicine, Section of Neurology, University of Piemonte Orientale "A. Avogadro", Novara, Italy. Electronic address: gionata.strigaro@gmail.com.
authors.forename: Gionata
authors.initials: G
authors.lastname: Strigaro
authors.affiliation: Department of Translational Medicine, Section of Neurology, University of Piemonte Orientale "A. Avogadro", Novara, Italy.
authors.forename: Lina
authors.initials: L
authors.lastname: Falletta
authors.affiliation: Department of Translational Medicine, Section of Neurology, University of Piemonte Orientale "A. Avogadro", Novara, Italy.
authors.forename: Annalisa
authors.initials: A
authors.lastname: Cerino
authors.affiliation: Department of Translational Medicine, Section of Neurology, University of Piemonte Orientale "A. Avogadro", Novara, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Pizzamiglio
authors.affiliation: Department of Translational Medicine, Section of Neurology, University of Piemonte Orientale "A. Avogadro", Novara, Italy.
authors.forename: Giacomo
authors.initials: G
authors.lastname: Tondo
authors.affiliation: Department of Translational Medicine, Section of Neurology, University of Piemonte Orientale "A. Avogadro", Novara, Italy.
authors.forename: Claudia
authors.initials: C
authors.lastname: Varrasi
authors.affiliation: Department of Translational Medicine, Section of Neurology, University of Piemonte Orientale "A. Avogadro", Novara, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Cantello
mesh_terms: D000328:Adult; D004558:Electric Stimulation; D019054:Evoked Potentials, Motor; D005260:Female; D006801:Humans; D017774:Long-Term Potentiation / Q000502:physiology*; D008297:Male; D008475:Median Nerve / Q000503:physiopathology; D008875:Middle Aged; D009044:Motor Cortex / Q000503:physiopathology*; D018482:Muscle, Skeletal / Q000503:physiopathology; D020190:Myoclonic Epilepsy, Juvenile / Q000503:physiopathology*; D050781:Transcranial Magnetic Stimulation; D055815:Young Adult
keywords: Juvenile myoclonic epilepsy; Paired associative stimulation; Synaptic plasticity; Transcranial magnetic stimulation