title: Effects of visual deprivation on primary motor cortex excitability: a study on healthy subjects based on repetitive transcranial magnetic stimulation.
abstract: We investigated whether rapid changes in visual input or dark adaptation modify primary motor cortex (M1) excitability in healthy subjects. Repetitive transcranial magnetic stimulation (rTMS), consisting of 10 stimuli delivered at 5 Hz at 120% of the resting motor threshold, was delivered over the M1 in 14 healthy volunteers. They were instructed to relax under eyes-open (EO) and eyes-closed (EC) resting conditions. Two experimental sessions were performed. In the first session, subjects were tested under both EO and EC conditions in order to determine whether short visual deprivation affected M1 excitability as tested through changes in the motor-evoked potential (MEP) amplitude during rTMS. In the second session, rTMS was delivered both under EO conditions with room lights on and after 30 min of blindfolding to evaluate the effects of prolonged visual deprivation on M1 excitability. Short-term visual deprivation lasting 2.5 s left the MEP facilitation unchanged during the 5-Hz rTMS trains, while 30 min of blindfolding significantly reduced MEP facilitation. Short-term visual deprivation did not significantly affect M1 excitability, whereas dark adaptation reduced rTMS-induced MEP facilitation, modulating motor cortical excitability.
authors.affiliation: Department of Neurology and Psychiatry, "Sapienza" University of Rome, Viale dell'Università 30, 00185, Rome, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Cambieri
authors.affiliation: Department of Neurology and Psychiatry, "Sapienza" University of Rome, Viale dell'Università 30, 00185, Rome, Italy.
authors.forename: Elisa
authors.initials: E
authors.lastname: Iacovelli
authors.affiliation: Department of Neurology and Psychiatry, "Sapienza" University of Rome, Viale dell'Università 30, 00185, Rome, Italy.
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Gori
authors.affiliation: Department of Neurology and Psychiatry, "Sapienza" University of Rome, Viale dell'Università 30, 00185, Rome, Italy.
authors.forename: Emanuela
authors.initials: E
authors.lastname: Onesti
authors.affiliation: Department of Neurology and Psychiatry, "Sapienza" University of Rome, Viale dell'Università 30, 00185, Rome, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Ceccanti
authors.affiliation: Department of Neurology and Psychiatry, "Sapienza" University of Rome, Viale dell'Università 30, 00185, Rome, Italy.
authors.forename: Vittorio
authors.initials: V
authors.lastname: Frasca
authors.affiliation: Department of Neurology and Psychiatry, "Sapienza" University of Rome, Viale dell'Università 30, 00185, Rome, Italy. maurizio.inghilleri@uniroma1.it.
authors.forename: Maurizio
authors.initials: M
authors.lastname: Inghilleri
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D004576:Electromyography; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005260:Female; D007839:Functional Laterality; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000502:physiology*; D010775:Photic Stimulation; D012683:Sensory Deprivation / Q000502:physiology*; D050781:Transcranial Magnetic Stimulation
keywords: Motor cortical excitability; Prolonged blindfolding; Repetitive transcranial magnetic stimulation (rTMS); Short-term visual deprivation