Daniel Yoshor, M.D. - US grants

DESCRIPTION (provided by applicant): A fundamental goal in neuroscience is to understand the link between the activity of neurons in the brain and perception. Object recognition is an important aspect of visual perception: Humans are readily able to rapidly recognize objects independent of variations in object size, position, illumination and pose. While a large body of work suggests that the inferotemporal cortex (IT) is involved in object recognition, many questions remain about the neuronal mechanisms that underlie object representations in the brain and how attention is directed to these representations. The proposed research will study these important questions by capitalizing on a unique opportunity to obtain neurophysiological recordings directly from human brain in awake, behaving patients. The PI will simultaneously record the electrophysiological activity in human IT and subjects' perceptual performance during a range of object recognition tasks that are designed to measure three important aspects of object recognition: invariance, attention, and reliability. These studies will be carried by the PI, a neurosurgeon with a clinical background in brain mapping and epilepsy surgery, under the primary mentorship of a senior neuroscientist with a primary interest in the neurophysiology of visual processing, and with additional mentoring from the Chair of the Department of Neurosurgery, who has extensive experience in basic and clinical neurophysiology applied in the operating room, and a senior neuropsychologist with expertise in human psychophysics. By enhancing our understanding of how the brain creates behaviorally relevant representations of the visual world, this research may help some of the millions of Americans who suffer from cognitive deficits such as visual agnosia after stroke or head injury. The research program will be complemented by coursework in neurophysiology and neuropsychology and by oversight by an advisory committee of experienced Baylor faculty that includes two neuroscientists, a neuropsychologist, a neurosurgeon, and a clinical neurophysiologist. Together, the research and training components of this career development award will serve as the foundation for the Pl's long term goal of establishing an independent research program in human cognitive neurophysiology.

Project Summary/Abstract Blindness disables millions of people across the world. In most cases, incurable blindness is caused by damage or dysfunction of the eye, retina, or optic nerve, but the visual cortex is undamaged and potentially functional. Electrical stimulation of visual cortex, even in blind patients, produces a percept of a distinct spots of light known as phosphenes. There has long been interest in developing a prosthetic device that employs direct activation of the intact visual cortex to restore vision to the blind. It has been speculated that phosphenes could serve as the building blocks for visual restoration in the blind; but unlike pixels in a video display, multiple phosphenes are not readily combined into a percept of a coherent form. We propose a novel stimulation paradigm, termed dynamic current steering, that can dramatically enhance the ability of visual cortical prosthetics (VCPs) to produce useful percepts of visual forms. Because there are imminent plans for clinical trials of several VCPs within the next few years, now is a currently particularly important time to develop improved methods for stimulation of visual cortex. To assess and refine dynamic current steering as a methodology for a VCP, we will measure percepts produced with this novel paradigm in pre-clinical testing in human epilepsy patients with implanted intracranial electrodes. In Aim 1, we will test dynamic current steering as a novel method for producing percepts of visual forms. In Aim 2, we will optimize the components of dynamic current steering to promote perception of coherent forms. Together, these aims will result in a novel paradigm for producing useful percepts of coherent visual forms by stimulation visual cortex that will be immediately translatable in forthcoming clinical trials of the next generation of VCPs.

DESCRIPTION (provided by applicant): The Baylor Neurosurgery Residency Program has been in place for over fifty years, and has long been one of the nation's largest and most well respected neurosurgical training programs. The program has always had a solid academic tradition, and graduates have served as faculty at many leading medical schools. Beginning in 2006, the program was retooled to substantially enhance its ability to train the next generation of academic neurosurgeons. In addition to developing a culture that emphasizes evidence-based practice, clinical and basic research, and didactic training in basic neuroscience underlying neurosurgical practice, the program was expanded by a full year in order to provide residents with a deeper and more meaningful research experience that will help prepare them for an academic career. The Baylor Research Education Program in Neurosurgery will carefully develop and oversee a full year dedicated to research, and will also integrate research education into the full seven year program. The hallmark of the resident research experience will be the twelve-month research block during the fourth year of the residency. To maximize research productivity, residents will also have a four-month research block in the preceding year to plan a project, write a research proposal, and begin data collection. Residents will also have an additional four- month research block during the year that follows the dedicated research year, in order to wrap up their projects, complete any remaining data analysis, and finish writing up manuscripts for publication. This presents a substantial commitment to research with a total of 20 months of protected research time. The primary goal of this research education program is to provide Neurosurgery residents with the opportunity to complete a cohesive, significant research project during their residency training. The program will mentor residents through the entire research process, from project conception to experimental design, data analysis and interpretation, and finally, to publication of results. This hands-on approach is the most effective way to prepare young clinician scientists for a productive research career by allowing them to conduct research independently, but with enough support to avoid the common pitfalls experienced by young researchers. This mentored project will also provide the resident with a foundation of data and expertise from which to build an independent research program and apply for research funding. This Program is therefore designed to provide a substantial level of oversight, while still ensuring flexibility for each resident to design his or her own research project. The Program is comprised of both research and educational plans for participants as well as formalized mentorship procedures and will span all seven years of residency training. PUBLIC HEALTH RELEVANCE: The primary goal of this research education program is to provide Neurosurgery residents with the opportunity to complete a cohesive, significant research project during their residency training. The program will mentor residents through the entire research process, from project conception to experimental design, data analysis and interpretation, and finally, to publication of results. This hands-on approach is the most effective way to prepare the next generation of young clinician scientists for a productive research career in Neurosurgery, Neuroscience, or Neuro-oncology.