RESEARCH AREAS
My research program examines coordination and adaptive learning of limb movements and how regions of the brain are involved in these tasks. We have developed a robotic exoskeleton called KINARM™ (Kinesiological Instrument for Normal and Altered Reaching Movements) with hinge joints that align to a subject’s shoulder and elbow and allows them to make arm movements in the horizontal plane. Custom-made fibreglass braces attach the linkage to the subject's forearm and arm. Motors attached to the mechanical linkage provide angular position of the joints and can apply torques either to the shoulder or elbow, or both. KINARM™ is used in concert with a computer projection system that provides virtual targets in the plane of the arm. There are several facilities currently using using the KINARM™, one of which is located at St. Mary's of the Lake Hospital. Much of my research program uses these facilities to examine a range of questions on motor coordination and learning. Product development is supported by CIHR-R&D, CIHR-POP, and ORDCF.
Review Articles
Scott, S.H. (2004) Optimal feedback control and the neural basis of volitional motor control. Nature Reviews Neuroscience 5: 532-546. (view)
Scott, S.H. (2003) Invited Review: The role of primary motor cortex in goal-directed movements: insights from neurophysiological studies on non-human primates. Current Opinion in Neurobiology 13:671-677. (view)
Scott, S.H. and Norman, K.E. (2003) Invited Review: Computational approaches to motor control and their potential role for interpreting motor dysfunction. Current Opinion in Neurology 16:693-698. (view)
Scott, S.H. (2000) Role of motor cortex in coordinating multi-joint movements: Is it time for a new paradigm? [Review] Canadian Journal of Physiology and Pharmacology 78:923-933. (view)
Scott, S.H. (1999) Apparatus for measuring and perturbing shoulder and elbow joint positions and torques during reaching. Journal of Neuroscience Methods 89:119-127. (view)
Neural Control of Movements in NHPs
My research program examines the neural control of movement, specifically related to the coordination of shoulder and elbow motion. We explore how regions of the brain, such as primary motor cortex, are involved in controlling limb movements. Our studies explore how neural activity relates to features of limb mechanics and physical loads applies to the limb. The studies illustrate the link between the mechanics of movement and neural processing. This research with NHPs is presently funded by the CIHR, and CIHR-NET.
Review Articles
Graham, K.M., Moore, K.D., Cabel, D.W., Gribble, P.L., Cisek, P. and Scott, S.H. (2003) Kinematics and kinetics of multi-joint reaching in non-human primates. Journal of Neurophysiology 89:2667 2777. (view)
Gribble, P.L. and Scott, S.H. (2002) Overlap of internal models in motor cortex for mechanical loads during reaching. Nature 417:938-941. (view)
Cabel, D.W., Cisek, P. and Scott, S.H. (2001) Neural activity in primary motor cortex related to mechanical loads applied to the shoulder and elbow during a postural task. Journal of Neurophysiology 86:2102-2108. (view)
Scott, S.H., Gribble, P.L., Graham, K.M. and Cabel, D.W. (2001) Dissociation between hand motion and population vectors from neural activity in motor cortex. Nature 413:161-165. (view)
Scott, S.H. and Kalaska, J.F. (1997) Reaching movements with similar hand paths but different arm orientations. I. Activity of individual cells in motor cortex. Journal of Neurophysiology 77:826-853. (view)
Scott, S.H., Sergio, L.H. and Kalaska, J.F. (1997) Reaching movements with similar hand paths but different arm orientations. II. Activity of individual cells in dorsal premotor and parietal area 5 cortex. Journal of Neurophysiology 78:2413-2426. (view)
Scott, S.H. (1997) Comparison of onset time and magnitude of activity for proximal arm muscles and motor cortical cells prior to reaching movements. Journal of Neurophysiology 77:1016-1022. (view)
Peripheral Motor Anatomy and Physiology
We have performed a series of morphometric studies on the anatomical organization of the proximal forelimb of non-human primates. These studies have documented a large number of parameters related to each muscle spanning the shoulder and elbow joints, the mechanical advantage of the major muscles involved in flexion and extension at these two joints as well as the inertial properties of the forelimb. We have also examined the mechanics of limb movement as well as the associated electromyographic activity of shoulder and elbow muscles during a range of whole limb motor tasks. Future projects will use this information to create realistic models of the primate forelimb in order to understand how the anatomical and physiological properties of the musculoskeletal system influence movement control and to aid in the interpretation of neural activity during movement and posture.
Review Articles
Graham, K.M. and Scott, S.H. (2003) Morphometry of Macaca mulatta forelimb. III. Moment arm of shoulder and elbow muscles. Submitted to Journal of Morphology 255:301-314. (view)
Singh, K., Melis, E.H., Richmond, F.J.R. and Scott, S.H. (2002) Morphometry of Macaca mulatta forelimb. II. Fiber-type composition in shoulder and elbow muscles. Journal of Morphology 251:323-332. (view)
Cheng, E.J. and Scott, S.H. (2000) Morphometry of Macaca mulatta forelimb. I. Shoulder and elbow muscles and segment inertial parameters. Journal of Morphology 245:206-224. (view)
Human Motor Control and Learning
A key to this research program is a new experimental paradigm and facility developed specifically to study the coordination of multi-joint movements of humans. A full-sized KINARM™ has been built and is presently being used in a number of projects. This research is supported by a grant from NSERC.
Review Articles
Singh, K. and Scott, S.H. (2003) A motor learning strategy reflecting neural circuitry for limb control. Nature Neuroscience 6:399-403. (view)
Sergio, L.H. and Scott, S.H. (1998) Hand and joint paths during reaching movements with and without vision. Experimental Brain Research 122:157-164. (view)
Mathematical Models
From time to time, we like to use mathematical models to examine both central and peripheral issues in sensorimotor control. We will soon begin more projects in this area. On the simplicity-to-complexity scale, we like to make them simple but insightful!
Review Articles
Gribble, P.L. and Scott, S.H. (2002) Method for assessing directional characteristics of non-uniformly sampled neural activity. Journal of Neuroscience Methods 113:185-195. (view)
Cisek, P. and Scott, S.H. (1999) An alternative interpretation of population vector rotation in macaque motor cortex. Neuroscience Letters 272:1-4. (view)
Scott, S.H. and Kalaska, J.F. (1997) Reaching movements with similar hand paths but different arm orientations. I. Activity of individual cells in motor cortex. Journal of Neurophysiology 77:826-853. (view)
Scott, S.H. and Loeb, G.E. (1994) The computation of position-sense from spindles in mono- and multi-articular muscles. Journal of Neuroscience 14:7529-7540. (view)