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        My research at the Bizzi lab focuses on how the central nervous system (CNS) achieves motor coordination, or the process by which the variables involved in movement planning and execution are assembled together to produce integrated behaviors.  Understanding motor coordination has been a long standing problem in neuroscience, because of (1) the complexity of the inverse dynamics problem, or the problem of specifying appropriate joint torques for producing a desired movement, and (2) the redundancy of the muscular system.  It has been proposed that the CNS circumvents these difficulties by generating motor patterns through flexible combination of a small number of muscle synergies located in the spinal cord.


      Supervised by Prof. Bizzi, and collaborating with Andrea d’Avella, PhD, and Matthew Tresch, PhD, I have been studying motor coordination by collecting electromyographical signals (EMGs) from all major hindlimb muscles of the frog during natural behaviors.  We have found that EMGs of all behaviors (kicking, jumping, swimming etc.) can be reconstructed by linearly combining 5-6 muscle synergies.  We have also developed a computational algorithm capable of simultaneously identifying muscle synergies shared by multiple EMG data sets, and synergies specific to each data set.  Applying this algorithm to data collected from both intact and deafferented frogs, we have shown that most locomotor synergies are centrally encoded within the spinal cord.

 

Publications

  • Bizzi E, Cheung VCK, d'Avella A, Saltiel P, Tresch M (2008) Combining modules for movement.  Brain Research Reviews 57: 125-133.  [PDF]
  • Tresch MC, Cheung VCK, d'Avella A (2006) Matrix factorization algorithms for the identification of muscle synergies: evaluation on simulated and experimental data sets.  Journal of Neurophysiology 95: 2199-2212.  [PDF]
  • Cheung VCK, Tresch MC (2005) Non-negative matrix factorization algorithms modeling noise distributions within the exponential family.  Proceedings of the 27th IEEE Engineering in Medicine and Biology Society Annual International Conference (September 1-4, 2005, Shanghai, China), 4990-4993.  [PDF]
  • Cheung VCK, d’Avella A, Tresch MC, Bizzi E (2005) Central and sensory contributions to the activation and organization of muscle synergies during natural motor behaviors.  Journal of Neuroscience 25(27): 6419-6434. [PDF]
  • Cheung VCK, Puil E (1999) Rhodium (Rh3+) actions on medial geniculate body neurons [Abstract].  Physiology Canada 30(3):155.  [PDF]
 
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Last updated on December 30, 2007