Nitish Thakor, Johns Hopkins School of Medicine
Brain signals carry the code for what we think and what we do. So, what is the code, and how can we decode the brain signals to convert thoughts into action, and action into function: such as moving the hand and finger in a prosthesis? First the brain signals come from neurons (spikes or action potential) but can be picked up from the cortex or the scalp (Electroencephalogram, EEG). First, I will present the basic and advanced applications of the EEG signal processing, mainly to interpret the subject's thought or intent to interact with a computer or a machine such as a robotic prosthetic hand. As an example, we can readily show that through thoughts a cursor can be moved on a computer screen or a prosthetic hand can be made to open and close. I will present the basic signal processing strategy, which essentially uses spectral analysis but must resolve independent signal components from the brain. Building on that idea, I will show that decoding neural spikes, or action potentials, from a population of neurons is required to achieve higher functionality - such as moving individual fingers or controlling a grasp in a prosthetic hand. I will present two strategies; maximum likelihood estimation and neural network algorithms optimized for experimental neuronal data for this particular application. I will conclude with the challenge to signal processors to develop approaches to interpreting brain rhythm so that brain-machine interface, brain control of computers, and interpreting complex sensory, motor and even more advanced cognitive intentions can be achieved. I will speculate on what applications might open up in the field of brain-machine interface?
Nitish V. Thakor received B. Tech. degree in electrical engineering from Indian Institute of Technology, Bombay, in 1974 and the Ph.D. degree in electrical and computer engineering from the University of Wisconsin, Madison, in 1981. He served on the faculty of Electrical Engineering and Computer Science of the Northwestern University between 1981 and 1983, and since then he has been with the Johns Hopkins University, School of Medicine, where he is currently serving as a Professor of Biomedical Engineering. He conducts research on neurological instrumentation, biomedical signal processing, micro and nanotechnologies, neural prosthesis, and clinical applications of neural and rehabilitation technologies. He has authored more than 170 peer-reviewed publications on these subjects. He is the Editor in Chief of IEEE Transactions on Neural and Rehabilitation Engineering. Currently he directs the Laboratory for Neuroengineering and is also the Director of the NIH Training Grant on Neuroengineering. One of his current research projects, in collaboration with a multi-University consortium, funded by DARPA, is to develop a next generation neurally controlled upper limb prosthesis. He is actively engaged developing international scientific programs, collaborative exchanges, tutorials and conferences in the field of Biomedical Engineering. Dr. Thakor is a recipient of a Research Career Development Award from the National Institutes of Health and a Presidential Young Investigator Award from the National Science Foundation. He is a Fellow of the American Institute of Medical and Biological Engineering, IEEE and Founding Fellow of the Biomedical Engineering Society. He is also a recipient of the Centennial Medal from the University of Wisconsin School of Engineering, Honorary Membership from Alpha Eta Mu Beta Biomedical Engineering student Honor Society and Distinguished Service Award from IIT Bombay.