title: Abnormal sensorimotor plasticity in migraine without aura patients.
abstract: The period between migraine attacks is characterized by paradoxical responses to repetitive sensory and transcranial magnetic stimulation (TMS). Abnormal long-term cortical functional plasticity may play a role and can be assessed experimentally by paired associative stimulation (PAS), in which somatosensory peripheral nerve stimuli are followed by TMS of the motor cortex. Changes in motor-evoked potential (MEP) amplitudes were recorded in 16 migraine without aura patients (MO) and 15 healthy volunteers (HV) before and after PAS, which consisted of 90 peripheral electrical right ulnar nerve stimulations and subsequent TMS pulses over the first dorsal interosseous (FDI) muscle activation site with a delay of 10 ms (excitability depressing) or 25 ms (excitability enhancing). As a control experiment of the 31 subjects studied, 8 (4 MO and 4 HV) also underwent PAS10 earlier, the recording of somatosensory high-frequency oscillations (HFOs) reflecting thalamocortical activation (early HFOs). Although PAS10 reduced MEP amplitudes in HV (-17.7%), it significantly increased amplitudes in MO (+35.9%). Although in HV MEP amplitudes were significantly potentiated (+55.1) after PAS25, only a slight, nonsignificant increase was observed in MO (+18.8%). In the control experiment, performed on 8 subjects pooled together, Pearson's correlation showed an inverse relationship between the percentage of MEP amplitude changes after PAS10 and early HFO amplitudes (r=-0.81; P=.01). Because we observed that the more deficient the long-term PAS-induced change, the more the thalamocortical activation decreased, we hypothesize that the abnormalities in long-term cortical plasticity observed in the interictal period between migraine episodes could be due to altered thalamic control.
authors.affiliation: IRCCS Neuromed, Pozzilli (IS), Italy "Sapienza" University of Rome, Department of Medicosurgical Sciences and Biotechnologies, Neurology Section, Rome, Italy "Sapienza" University of Rome, Department of Medicosurgical Sciences and Biotechnologies, Latina, Italy G.B. Bietti Foundation-IRCCS, Department of Neurophysiology of Vision and Neurophthalmology, Rome, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Pierelli
authors.forename: Elisa
authors.initials: E
authors.lastname: Iacovelli
authors.forename: Martina
authors.initials: M
authors.lastname: Bracaglia
authors.forename: Mariano
authors.initials: M
authors.lastname: Serrao
authors.forename: Gianluca
authors.initials: G
authors.lastname: Coppola
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D004558:Electric Stimulation; D004576:Electromyography; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D020326:Migraine without Aura / Q000473:pathology* / Q000503:physiopathology; D013003:Somatosensory Cortex / Q000503:physiopathology*; D050781:Transcranial Magnetic Stimulation; D014459:Ulnar Nerve / Q000502:physiology
keywords: High-frequency oscillations; Paired associative stimulation; Thalamocortical fibers; Transcranial magnetic stimulation