Emilio Bizzi
Massachusetts Institute of Technology
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Primary Section: 28, Systems Neuroscience Membership Type:
Member
(elected 1986)
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Research Interests
My research focuses on the study of the physiological mechanisms underlying complex coordinated movements. My investigations have dealt with the mechanisms whereby the central nervous system (CNS) simultaneously controls the large number of degrees of freedom of the multi-joint musculo-skeleteal system and the nature of the interactions between motor programs and afferent feedback originating from moving body parts. Experimental results suggest that arm trajectory is controlled by neural signals that specify a series of equilibrium positions for the limb. According to this equilibrium-position hypothesis, the muscle's spring-like properties generate the necessary joint torques, implicitly providing an approximated solution to the dynamics problem. Recently, my collaborators and I have provided evidence showing that the neural circuits in the spinal cord are organized into a number of distinct functional modules. Simultaneous activation of these modules generates forces in the limb proportional to the vector sum of the forces induced by the separate stimulation of each module. The observation of vectorial combination of motor outputs led us to the formulation of a new framework of how the CNS may control motor behavior based on the idea that supraspinal commands generate a variety of different movements by selecting different combinations of the modules.
