F-wave 1 abducens nerve 1 abductor digiti minimi (ADM) 1 adult 1 article 1 clinical article 1 controlled study 1 electromyography 1 enslaving effect human 1 human experiment 1 imagery 1 index finger 1 leisure 1 male 1 motoneuron 1 motor imagery (MI) 1 muscle function 1 nerve cell excitability 1 spinal motor neuron (SMN) 1 thenar 1 thumb 1