The motor system plays the violin: a musical metaphor inferred from the oscillatory activity of the α-motoneuron pools during locomotion.

Despite substantial advances in the field, particularly resulting from physiological studies in animals, the neural mechanisms underlying the generation of many motor behaviors in humans remain unclear. A recent study (Cappellini G et al. J Neurophysiol 104: 3064-3073, 2010) sheds more light on this topic. Like the string of a violin, the α-motoneuron pools in the spinal cord during locomotion show continuous and oscillatory patterns of activation. In this report, the implications and relevance of this finding are discussed in a general framework that includes neurophysiology, optimal control theory, and robotics.