Events Calendar

Engineering Neuroscience & Health Seminar

Speaker: Dr. Tim Carroll, University of Queensland, Brisbane, Australia

Talk Title: Multiple spatial coordinate systems for new maps between sensory information and motor commands

Abstract: Humans can learn to make accurate movements when the required map between sensory inputs and motor commands changes, such as when using tools that alter limb dynamics or when sensory information is distorted. Moreover, motor learning can also involve a “use-dependent” component that biases subsequent movements towards those repeated during practice, but that does not require the correction of movement errors. A key question regarding the sensorimotor adaptations that underlie this flexibility is the spatial frame of reference in which remapping is encoded. Are new sensorimotor maps defined according to the particular joint angles or torques required for movement, the native coordinate systems of the relevant sensory information (e.g. retinotopic motion direction), or composite extrinsic coordinate systems such as Cartesian space relative to the body? We have addressed this question in a series of visuomotor adaptation studies in which subjects had to move a cursor to visual targets by exerting isometric forces with the finger or wrist. We assessed how adaptation of the initial movement direction generalized to new target directions, postures and between left and right limbs, to systematically manipulate the alignment of the learned perturbation in various spatial coordinate systems. For transfer of visuomotor adaptation between left and right limbs, and generalization of visuomotor gain adaptation, transfer of adaptation only occurred when visuomotor distortion had identical effects in eye- and joint-based coordinates bilaterally. However, generalization of visoumotor adaptation to different postures within a single limb, and bias in force direction generated in response to repetition of a single movement direction were expressed according to a purely extrinsic or visual (rather than limb-based) reference frame. The results imply that new visuomotor maps are encoded in neural circuits associated with both intrinsic and extrinsic movement representations, but that the behavioral outcomes of remapping (i.e. generalization patterns) depend on the sensory context.

Biography: Dr Carroll completed his doctorate in Neuroscience at the University of Queensland in 2001. He was awarded an Isaac Walton Killam Memorial Scholarship to pursue postdoctoral studies at the University of Alberta in 2002, before accepting a position as a Lecturer in Human Motor Control at the University of New South Wales in 2003. He joined the School of Human Movement Studies as a Senior Lecturer in July 2007.

Dr Carroll’s research interests lie in the broad field of integrative human physiology. His work spans the fields of exercise science and integrative neuroscience, with a focus on determining how the central nervous system is reorganised as a consequence of motor learning and exercise. He has a specific interest in the area of strength training. Dr Carroll’s research involves the application of electro-physiological techniques such as Transcranial Magnetic Stimulation (TMS), peripheral nerve stimulation, and electromyography (EMG) in experiments involving human subjects. The ultimate purpose of his work is to generate basic knowledge that will lead to the development of exercise protocols that yield maximal benefits for rehabilitation and injury prevention. His work has been funded by the Australian Research Council (ARC) since 2004


Host: Dr. Francisco Valero-Cuevas/Dr.Gerald Loeb/Dr. Terry Sanger

More Info: http://bbdl.usc.edu

Webcast: http://capture.usc.edu/college/Catalog/?cid=af180d48-ceff-42b9-a35c-eb199daed320

More Information: Tim Carroll Flyer.pdf

Location: Center For Health Professions (CHP) - 147

WebCast Link: http://capture.usc.edu/college/Catalog/?cid=af180d48-ceff-42b9-a35c-eb199daed320

Audiences: Everyone Is Invited

Contact: BME-ENH Seminar

Event Link: http://bbdl.usc.edu