Hubert H. Lim, PhD
Professor, Department of Otolaryngology, Head and Neck Surgery
Faculty, Graduate Program in Neuroscience
Hannover Medical University (Otorhinolaryngology), 2006-2009
PhD, University of Michigan (Biomedical Engineering), 2005
MSE, University of Michigan (Biomedical Engineering), 2002
MSE, University of Michigan (Electrical Engineering and Computer Science), 2004
BS, University of California (Bioengineering), 2000
Neural Prostheses, Auditory Neuroscience, Neural Plasticity
The goal of my lab is to push the development and translation of brain-machine interfaces from scientific concept into clinical application with close collaboration with clinicians and industry. Brain-machine interfaces span a broad array of applications and consist of either direct connection of a device to neurons within the brain or neural communication through noninvasive techniques, such as EEG recordings and transcranial magnetic stimulation. The initial focus of my lab is to develop and improve implantable neural prostheses for restoring auditory function in deaf or hearing-impaired patients as well as those experiencing severe tinnitus (i.e., a phantom auditory percept that persists without any actual sound input). There are several auditory implants currently used in humans. This includes the cochlear implant (stimulates auditory nerve fibers), the auditory brainstem implant (stimulates the cochlear nucleus), and the auditory midbrain implant (stimulates the inferior colliculus), which my colleagues and I recently developed and translated into a clinical device. Some of these implants, as well as a few recent cortical devices, have also been used to suppress tinnitus. Although the outcomes have been encouraging, there are still many limitations with these devices, such as poor hearing in noisy environments and substantial variability in performance across patients. One fundamental limitation in improving these devices has been the lack of understanding of how the central auditory system in humans processes and represents sound information.
My lab employs various experimental and engineering techniques in animals (e.g., guinea pig, cat) and humans to understand the human brain and how to successfully implement a neural device. This includes acute and chronic implantation of electrode arrays into the animal brain to investigate how the auditory system codes for different sound features as well as the effects of electrical activation of multiple auditory and nonauditory pathways on sound coding and perception. Various electrophysiological and modeling techniques are also used to investigate the descending and plasticity circuitry of the auditory system, which is important for understanding how to improve and optimize stimulation strategies for restoring hearing as well as suppressing tinnitus. By performing EEG and psychophysical studies in humans in response to acoustic and electrical stimulation and linking these results to those obtained in animals, we then obtain a better understanding of sound processing within the human brain that can guide the development of the next generation of auditory implants.
Although the initial focus of my lab is to develop improved auditory implants, we will expand our techniques and technologies to develop improved neural prostheses for other clinical applications, especially those investigated by other leading research groups at University of Minnesota (e.g., epilepsy, pain, motor control).
- The Auditory Midbrain Implant: Effects of electrode location. Lim HH, Lenarz T, Anderson DJ, Lenarz M Hearing Research 242: 74-85, 2008
- Effects of phase duration and pulse rate on loudness and pitch percepts in the first auditory midbrain implant patients: Comparison to cochlear implant and auditory brainstem implant results. Lim HH, Lenarz T, Joseph G, Battmer RD, James F. Patrick, Lenarz M. Neuroscience 154(1): 370-380, 2008
- Dynamic models of neural spiking activity. Czanner G, Dreyer AA, Eden UT, Wirth S, Lim HH, Suzuki WA, Brown EN. Proceedings of the 46th IEEE Conference on Decision & Control, 5812-5817, 2007
- Electrical stimulation of the midbrain for hearing restoration: Insight into the functional organization of the human central auditory system. Lim HH, Lenarz T, Joseph G, Battmer RD, Samii A, Samii M, Patrick JF, Lenarz M. Journal of Neuroscience 27(49): 13541-13551, 2007
- Auditory Midbrain Implant: Histomorphological effects of long-term implantation and electrical stimulation of a new DBS array. Lenarz M, Lim HH, Reuter G, Reich U, Marquardt N, Klingberg MN, Paasche G, Lenarz T, Stan A. Otology & Neurotology 28: 1045-1052, 2007
- Spatially distinct functional output regions within the central nucleus of the inferior colliculus: Implications for an Auditory Midbrain Implant. Lim HH, Anderson DJ. Journal of Neuroscience 27(32): 8733-8743, 2007
- Antidromic activation reveals tonotopically organized projections from primary auditory cortex to the central nucleus of the inferior colliculus in guinea pig. Lim HH, Anderson DJ. Journal of Neurophysiology 97: 1413-1427, 2007
- Auditory Midbrain Implant - A combined approach for vestibular schwannoma surgery and device implantation. Samii A, Lenarz M, Majdani O, Lim HH, Samii M, Lenarz T. Otology & Neurotology 28: 31-38, 2007
- Electrophysiological validation of a human prototype auditory midbrain implant (AMI) in a guinea pig model. Lenarz M, Lim HH, Patrick JF, Anderson DJ, Lenarz T. Journal of the Association for Research in Otolaryngology 7: 383-398, 2006
- Auditory cortical responses to electrical stimulation of the inferior colliculus: Implications for an auditory midbrain implant. Lim HH, Anderson DJ. Journal of Neurophysiology 96: 975-988, 2006
- Feasibility experiments for the development of a midbrain auditory prosthesis. Lim HH, Anderson DJ. Proceedings of the 1st International IEEE EMBS Conference on Neural Engineering, 193-196, 2003