Active Research Projects

Jeremy Greenlee, MD

Sponsor: Medtronic  
Project Title: Artificial Cervical Disc-LP Pivotal Study (2-Level)

Sponsor: National Institutes of Health
Project Title: Speech Sound Processing within Human Auditory Cortex during Self-Vocalization
Project Period: 04/1/09-3/31/14

During expressive speech, acoustic stimuli from both self-generated and environmental sound sources are continually processed within the auditory system. This information is used to adjust and optimize speech output through a poorly characterized feedback network. This network is thought to be dysfunctional in a variety of speech disorders, including stuttering, and may be impaired in some patients with psychoses. Despite the importance of this neural system, little is known about how auditory cortex functions when humans vocalize. In this proposal I plan to study this system using invasive experimental methods in epilepsy surgery patient volunteers. By using direct electrophysiologic recording and stimulation techniques, as well as reversible focal cooling, it is feasible to obtain information about the functional organization of human auditory cortex during vocalization that cannot be obtained using non-invasive methods. My specific aims are to 1) identify and characterize differences in auditory evoked responses recorded during vocalization and when these vocalizations are played back, 2) characterize how auditory feedback alterations during vocalization changes activity recorded from auditory cortex, 3) test the hypothesis that frontal lobe speech areas are functionally connected to the auditory cortical fields that demonstrate vocalization-induced changes in sound processing, and 4) use a cortical cooling method to reversibly deactivate frontal lobe sites and examine how this effects speech sound processing in functionally connected temporal lobe sites during vocalization.  

David Hasan, MD

Sponsor: National Institutes of Health
Project Title: Aneurysm Sac Growth as the Etiology of Recurrence in Coiled Cerebral Aneurysms
Project Period: 2/1/12-1/31/14 

The mechanisms of recurrence in intracranial aneurysms treated by coil embolization are poorly understood. Recurrence is often thought to be due to compaction of the coil mass in the aneurysm sac, but this premise has not been rigorously assessed. An alternative cause for angiographic recurrence after coiling these lesions could be that the aneurysm sac has grown, leading to new space for recanalization. Currently it is unclear whether both explanations of recurrence are equally common or one of them predominates. This proposal will access the validity of either of these explanations. 

Patrick W. Hitchon, MD

Sponsor: Asubio Pharmaceuticals, Inc.
Project Title: A Multicenter, Randomized, Double-Blind, Placebo-Controlled, Parallel-Group Study to Evaluate the Efficacy, Safety, and Pharmacokinetics of SUN13837 Injection in Adult Subjects with Acute Spinal Cord Injury.

Matthew Howard, MD

Sponsor: National Institutes of Health
Project Title: Human Auditory Cortex Physiology
Project Period: 08/1/00-11/30/15

Speech sounds are the most important sounds that we hear, yet little is known about how these stimulie are represented within human cerebral cortex. The goal of our research is to understand the functional organizations and connections of those areas of human cerebral cortex that are engaged in wound processing and examine how auditory and visual speech stimuli are represented in these regions. These experiments involve direct electrophysiological recording from an electrical stimulation of the cerebral cortex of awake human subjects undergoing clinical evaluation of intractable epilepsy. 

Sponsor: University of Wisconsin—Madison
Project Title: CRCNS: Decoding a Goal-Directed Valuation in the Human Amygdala
Project Period: 09/1/09-08/31/13

This proposal describes a research agenda, based on a heavily cross-disciplinary collaboration between a computational neuroscientists (Rick Jenison), a neurosurgeon and human electrophysiologist(Matt Howard), and a neuroeconomist (Antonio Rangel), that seeks to overcome all of these limitations at once in order to provide a more informed answer to the question of whether or not the amygdala plays a causal role in value-based role in choice. We have the opportunity to record single-unit activity from the amygdala complex in awake behaving human patients with pharmacologically intractable epilepsy. We are fortunate in that electrodes, by necessity, are almost always placed within the amygdala complex. Furthermore, with MRI reconstruction we know precisely where in the brain the electrode contacts are located.

Sponsor: Newcastle University/Wellcome Trust of London, United Kingdom
Project Title: Cortical Bases for Auditory Perception
Project Period: 12/1/10-11/30/15 

Arnold H. Menezes, MBBS

Sponsor: Park-Reeves Syringomyelia Research Consortium, 

The Park-Reeves Syringomyelia Research Consortium is a multi-institutional North American research effort founded to improve the medical and surgical care of children with syringomyelia related to Chiari I malformation. Through collaboration, we will work to enrich the lives and prevent disability in those affected by this condition.

Kirill Nourski, MD, PhD

Sponsor: Hearing Health Foundation
Project Title: Temporal Processing in Human Auditory Cortex
Project Period: 7/1/11-6/30/13

Human speech is a highly dynamic signal characterized by temporal fluctuations occurring on several scales. Relatively low frequency (<50 Hz) envelope information conveys segmental and prosodic cues essential to language understanding. The auditory cortex plays a critical role in processing these cues as it carries out its function in speech communication. The long-term objective of the project is to gain better understanding of how human auditory cortex processes perceptually significant temporal features of speech sounds. Innovative research methodology involves direct recordings from the auditory cortex, obtained using multicontact electrode arrays implanted in neurosurgical patients undergoing chronic invasive monitoring for medically refractory epilepsy. This project seeks to characterize representation of temporal envelope information within different auditory cortical fields and to determine task-related effects on cortical representation of envelope information. This will be achieved using a variety of speech and non-speech acoustic stimuli, presented within a context of behavioral tasks. Understanding of the auditory cortical function in is a key prerequisite for development of successful restoration and rehabilitation strategies in hearing-impaired individuals.