Title: Development of a universal, biomimetic Brain-Computer Interface: Are we decoding from a tortured manifold?
Abstract: The greatest desire for most people with high-level spinal cord injury is for restored hand movement. My lab developed an intracortical brain-computer interface (iBCI) in monkeys that used multi-electrode recordings from the motor cortex to “decode” muscle activity (EMG) in real-time. We used these decoded signals to modulate electrical stimulation of temporarily paralyzed muscles of the monkey’s hand to restore rudimentary voluntary movement. Our goal is to extend this approach to more complex motor actions, and to translate the methods to humans.
The ability to record simultaneously from many neurons also led to the concept of a low-dimensional “neural manifold” representing movement-related activity in the brain. We have examined the representation of a broad range of behaviors, which occupy different regions of this neural state space. A decoder trained on all behaviors is fairly accurate (though less so that single-behavior decoders). A piecewise linear decoder, that finds and decodes from distinct clusters within the space is much more accurate. However, any left-out behaviors are essentially undecodable, with linear or nonlinear methods. even with interpolation from surrounding areas. Our recent efforts have been devoted to understanding the shape and tortuosity of the manifold, and its relation to motor behavior and decoding.
Bio: Lee Miller is a Professor of Neuroscience at the Northwestern University Feinberg School of Medicine. The three fundamental goals of his research are the following: 1) To understand the nature of the brain's own signals -- the "language" in which movement commands are expressed by neurons in the central nervous system. 2) To understand the mechanisms by which these signals are produced -- the nature of the connections among networks of neurons, and the transformations that occur in the signals as they propagate throughout these networks. 3) To develop applications of these basic principles that could be of therapeutic value to human patients. Much of this work is done in collaboration with students and faculty from the Biomedical Engineering Department and the Interdepartmental Neuroscience Program (NUIN).
The NSF-Simons National Institute for Theory and Mathematics in Biology Seminar Series aims to bring together a mix of mathematicians and biologists to foster discussion and collaboration between the two fields. The seminar series will take place on Fridays from 10am - 11am at the NITMB in the John Hancock Center in downtown Chicago. There will be both an in-person and virtual component.