How the human brain controls hand movements to carry out different tasks is still debated. The concept of synergy has been proposed to indicate functional modules that may simplify the control of hand postures by simultaneously recruiting sets of muscles and joints. However, whether and to what extent synergic hand postures are encoded as such at a cortical level remains unknown. Here, we combined kinematic, electromyography, and brain activity measures obtained by functional magnetic resonance imaging while subjects performed a variety of movements towards virtual objects. Hand postural information, encoded through kinematic synergies, were represented in cortical areas devoted to hand motor control and successfully discriminated individual grasping movements, significantly outperforming alternative somatotopic or muscle-based models. Importantly, hand postural synergies were predicted by neural activation patterns within primary motor cortex. These findings support a novel cortical organization for hand movement control and open potential applications for brain-computer interfaces and neuroprostheses.
Human subjects: This study was approved by the Ethical Committee at the University of Pisa, Italy. Participants received a detailed explanation of all the study procedures and risks and provided a written informed consent according to the protocol approved by the University of Pisa Ethical Committee (1616/2003). All participants retained the right to withdraw from the study at any moment.
- Jody C Culham, University of Western Ontario, Canada
© 2016, Leo et al.
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