Ambra Bisio1, Laura Avanzino2, Nicolas Gueugneau2, Thierry Pozzo3, Piero Ruggeri2, Marco Bove4. 1. Department of Experimental Medicine, Section of Human Physiology and Centro Polifunzionale di Scienze Motorie, University of Genoa, 16132 Genoa, Italy; Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, 16132 Genoa, Italy. 2. Department of Experimental Medicine, Section of Human Physiology and Centro Polifunzionale di Scienze Motorie, University of Genoa, 16132 Genoa, Italy. 3. Department of Robotics, Brain and Cognitive Sciences, Istituto Italiano di Tecnologia, 16163 Genoa, Italy; INSERM, U1093, Cognition Action Plasticité Sensori Motrice, 21065 Dijon, France; Institut Universitaire de France, Université de Bourgogne, Campus Universitaire, UFR STAPS, Dijon, France. 4. Department of Experimental Medicine, Section of Human Physiology and Centro Polifunzionale di Scienze Motorie, University of Genoa, 16132 Genoa, Italy. Electronic address: marco.bove@unige.it.
Abstract
OBJECTIVE: To test whether action observation combined with peripheral nerve electrical stimulation was able to evoke plasticity in the primary motor cortex (M1). METHODS: The stimulation protocol consisted in the observation of a video showing repetitive thumb-index tapping movements (AO) combined with peripheral electrical nerve stimulation (PNS) delivered on the median nerve (AO-PNS). M1 excitability, measured by means of transcranial magnetic stimulation, was compared with that assessed after AO and PNS alone. RESULTS: M1 excitability increased after AO-PNS, whilst no modifications occurred after AO and PNS alone. The increased M1 excitability after AO-PNS was long-lasting (45 min) and specific for the stimulated muscle. CONCLUSIONS: This study described an innovative stimulation paradigm that exploited the mirror neuron system to induce plasticity in M1. However, this occurred only when action observation was combined with afferent signals coming from periphery. SIGNIFICANCE: This study supports the literature proposing the mirror neuron system as neural substrate for rehabilitation and opens a debate on the rehabilitative treatments that employ AO to improve patients' motor functions. Indeed, these results suggest that AO has to be combined with afferent inputs from periphery to evoke plasticity in the human motor system.
OBJECTIVE: To test whether action observation combined with peripheral nerve electrical stimulation was able to evoke plasticity in the primary motor cortex (M1). METHODS: The stimulation protocol consisted in the observation of a video showing repetitive thumb-index tapping movements (AO) combined with peripheral electrical nerve stimulation (PNS) delivered on the median nerve (AO-PNS). M1 excitability, measured by means of transcranial magnetic stimulation, was compared with that assessed after AO and PNS alone. RESULTS: M1 excitability increased after AO-PNS, whilst no modifications occurred after AO and PNS alone. The increased M1 excitability after AO-PNS was long-lasting (45 min) and specific for the stimulated muscle. CONCLUSIONS: This study described an innovative stimulation paradigm that exploited the mirror neuron system to induce plasticity in M1. However, this occurred only when action observation was combined with afferent signals coming from periphery. SIGNIFICANCE: This study supports the literature proposing the mirror neuron system as neural substrate for rehabilitation and opens a debate on the rehabilitative treatments that employ AO to improve patients' motor functions. Indeed, these results suggest that AO has to be combined with afferent inputs from periphery to evoke plasticity in the human motor system.