title: Remote effects of cortical dysgenesis on the primary motor cortex: evidence from the silent period following transcranial magnetic stimulation.
abstract: OBJECTIVE
  In cortical dysgenesis (CD), animal studies suggested abnormal cortico-cortical connections. Cerebral areas projecting to the primary motor cortex (M1) modulate the cortical silent period (CSP) following transcranial magnetic stimulation (TMS). Therefore, we used the CSP to investigate remote effects of CD on the M1.
  
  
  METHODS
  A detailed investigation, including single-pulse TMS and electrical nerve stimulation, was performed in 3 consecutive adults with focal CD located outside the M1 and in 18 controls. Two patients with unilateral CD were epileptic and treated with anti-epileptic drugs. One patient with focal CD on both sides had no history of seizures. Neurological examination was normal in all patients. Recordings were made from both first dorsal interosseous muscles.
  
  
  RESULTS
  In CD patients, the CSP was significantly lengthened contralaterally to the affected hemispheres. In treated patients with unilateral CD, the interside difference of the CSP duration was also significantly increased. In contrast, excitability threshold, peripheral and corticospinal motor conduction studies, and peripheral as well as ipsilateral silent periods were not significantly modified.
  
  
  CONCLUSIONS
  Our findings indicate that focal CD outside the M1 may produce CSP modifications, which are likely due to changes of afferent control.
authors.affiliation: Unita' Operativa di Neurologia, Azienda Sanitaria N.10 - Firenze, Ospedale S. Maria Nuova, Piazza S. Maria Nuova, 1, 50122, Firenze, Italy. cincotta@unifi.it
authors.forename: M
authors.initials: M
authors.lastname: Cincotta
authors.forename: A
authors.initials: A
authors.lastname: Borgheresi
authors.forename: L
authors.initials: L
authors.lastname: Guidi
authors.forename: M
authors.initials: M
authors.lastname: Macucci
authors.forename: M
authors.initials: M
authors.lastname: Cosottini
authors.forename: P
authors.initials: P
authors.lastname: Lambruschini
authors.forename: F
authors.initials: F
authors.lastname: Benvenuti
authors.forename: G
authors.initials: G
authors.lastname: Zaccara
mesh_terms: D000328:Adult; D004569:Electroencephalography; D017029:Epilepsy, Complex Partial / Q000473:pathology / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009044:Motor Cortex / Q000002:abnormalities*; D009132:Muscles / Q000503:physiopathology; D050781:Transcranial Magnetic Stimulation