title: Motor Cortical Plasticity to Training Started in Childhood: The Example of Piano Players.
abstract: Converging evidence suggest that motor training is associated with early and late changes of the cortical motor system. Transcranial magnetic stimulation (TMS) offers the possibility to study plastic rearrangements of the motor system in physiological and pathological conditions. We used TMS to characterize long-term changes in upper limb motor cortical representation and interhemispheric inhibition associated with bimanual skill training in pianists who started playing in an early age. Ipsilateral silent period (iSP) and cortical TMS mapping of hand muscles were obtained from 30 strictly right-handed subjects (16 pianists, 14 naïve controls), together with electromyographic recording of mirror movements (MMs) to voluntary hand movements. In controls, motor cortical representation of hand muscles was larger on the dominant (DH) than on the non-dominant hemisphere (NDH). On the contrary, pianists showed symmetric cortical output maps, being their DH less represented than in controls. In naïve subjects, the iSP was smaller on the right vs left abductor pollicis brevis (APB) indicating a weaker inhibition from the NDH to the DH. In pianists, interhemispheric inhibition was more symmetric as their DH was better inhibited than in controls. Electromyographic MMs were observed only in naïve subjects (7/14) and only to voluntary movement of the non-dominant hand. Subjects with MM had a lower iSP area on the right APB compared with all the others. Our findings suggest a more symmetrical motor cortex organization in pianists, both in terms of muscle cortical representation and interhemispheric inhibition. Although we cannot disentangle training-related from preexisting conditions, it is possible that long-term bimanual practice may reshape motor cortical representation and rebalance interhemispheric interactions, which in naïve right-handed subjects would both tend to favour the dominant hemisphere.
authors.affiliation: Department of Neurology, Scientific Institute Hospital San Raffaele, Milan Italy.|Experimental Neurophysiology Unit, Institute of Experimental Neurology (INSPE), Scientific Institute Hospital San Raffaele, Milan Italy.|University Vita-Salute San Raffaele, Milan, Italy.
authors.forename: Raffaella
authors.initials: R
authors.lastname: Chieffo
authors.affiliation: Department of Neurology, Scientific Institute Hospital San Raffaele, Milan Italy.|Experimental Neurophysiology Unit, Institute of Experimental Neurology (INSPE), Scientific Institute Hospital San Raffaele, Milan Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Straffi
authors.affiliation: Experimental Neurophysiology Unit, Institute of Experimental Neurology (INSPE), Scientific Institute Hospital San Raffaele, Milan Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Inuggi
authors.affiliation: Experimental Neurophysiology Unit, Institute of Experimental Neurology (INSPE), Scientific Institute Hospital San Raffaele, Milan Italy.
authors.forename: Javier J
authors.initials: JJ
authors.lastname: Gonzalez-Rosa
authors.affiliation: Department of Neurology, Scientific Institute Hospital San Raffaele, Milan Italy.|Experimental Neurophysiology Unit, Institute of Experimental Neurology (INSPE), Scientific Institute Hospital San Raffaele, Milan Italy.|University Vita-Salute San Raffaele, Milan, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Spagnolo
authors.affiliation: Department of Neurology, Scientific Institute Hospital San Raffaele, Milan Italy.|Experimental Neurophysiology Unit, Institute of Experimental Neurology (INSPE), Scientific Institute Hospital San Raffaele, Milan Italy.|University Vita-Salute San Raffaele, Milan, Italy.
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Coppi
authors.affiliation: Department of Neurology, Scientific Institute Hospital San Raffaele, Milan Italy.|Experimental Neurophysiology Unit, Institute of Experimental Neurology (INSPE), Scientific Institute Hospital San Raffaele, Milan Italy.|University Vita-Salute San Raffaele, Milan, Italy.
authors.forename: Arturo
authors.initials: A
authors.lastname: Nuara
authors.affiliation: Experimental Neurophysiology Unit, Institute of Experimental Neurology (INSPE), Scientific Institute Hospital San Raffaele, Milan Italy.
authors.forename: Elise
authors.initials: E
authors.lastname: Houdayer
authors.affiliation: Department of Neurology, Scientific Institute Hospital San Raffaele, Milan Italy.|Experimental Neurophysiology Unit, Institute of Experimental Neurology (INSPE), Scientific Institute Hospital San Raffaele, Milan Italy.|University Vita-Salute San Raffaele, Milan, Italy.
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Comi
authors.affiliation: Department of Neurology, Scientific Institute Hospital San Raffaele, Milan Italy.|Experimental Neurophysiology Unit, Institute of Experimental Neurology (INSPE), Scientific Institute Hospital San Raffaele, Milan Italy.
authors.forename: Letizia
authors.initials: L
authors.lastname: Leocani
mesh_terms: D000328:Adult; D000367:Age Factors; D000465:Algorithms; D000704:Analysis of Variance; D001931:Brain Mapping; D002648:Child; D002675:Child, Preschool; D019054:Evoked Potentials, Motor; D005260:Female; D006225:Hand / Q000502:physiology; D006801:Humans; D008297:Male; D008962:Models, Theoretical; D009044:Motor Cortex / Q000502:physiology*; D009068:Movement; D009473:Neuronal Plasticity / Q000502:physiology*; D011597:Psychomotor Performance; D050781:Transcranial Magnetic Stimulation; D055815:Young Adult