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ARO Seminar Series

These webinar session are free to attend and are recorded for later viewing. Closed captioning is available during the live and recorded sessions. The webinar sessions will rotate dates and times to be inclusive of all time zones. Please contact headquarters@aro.org with any questions.  

Dr. Jennifer Stone-  ‘Regeneration of Hair Cells After Damage: A Historical Perspective and an Update on Mammals’

Dr. Jenny Stone is a Professor in the Department of Otolaryngology-Head and Neck Surgery at the University of Washington School of Medicine. Her research focuses on cellular and molecular mechanisms that control the development and regeneration of hair cells, the sensory receptors for hearing and balance. She studies both avian and mammalian animal models.

This session was moderated by, Dr. Mark Warchol.

When: Thursday, November 12th at 6:00 PM ET.

Click here to view the webinar recording

 

Dr. Anthony Peng-  ‘Observations During the Study of Hair Cell Mechanotransduction’

Dr. Anthony Peng, Assistant Professor in the Department of Physiology and Biophysics at the University of Colorado Anschutz Medical Campus. His talk was titled ‘Observations During the Study of Hair Cell Mechanotransduction’.

Dr. Anthony Peng is an Assistant Professor in the Department of Physiology and Biophysics at the University of Colorado Anschutz Medical Campus. His lab is focused on studying the mechanisms of how the auditory sensory hair cells, the fastest mechanoreceptors in the body, transduce sound into electrical signals for the brain to process and interpret. To study the fast-mechanical responses of hair cells, Dr. Peng developed high-speed stimulators and high-speed imaging techniques to capture the kinetics of these exquisitely fast mechanoreceptors. Prior to starting his lab, Dr. Peng trained at Stanford University and in the Speech and Hearing Bioscience and Technology Program at Harvard and MIT.

This session was moderated by, Dr. Artur Indzhykulian.

When: Thursday, October 15th at 12:00 PM ET.

Click here to view the webinar recording Click here to view the presentation slides 

 

Dr. William Brownell- ‘From Sound to Action Potentials – A Tour of the Inner Ear’

Dr. William Brownell, Emeritus Professor at College of Medicine, speaks as the first presenter in the new ARO Seminar Series. His talk was titled ‘From Sound to Action Potentials – A Tour of the Inner Ear’.

Dr. Bill Brownell is professor emeritus at the Baylor College of Medicine, Houston, TX where he held the Jake and Nina Kamin Chair of Otorhinolaryngology. Previously held appointments were at the University of Florida, Gainesville, FL, and the Johns Hopkins School of Medicine, Baltimore, MD. He spent two years (1965-1966) teaching science and mathematics in Nigeria with the United States Peace Corps between his undergraduate training in physics and graduate training in physiology at the University of Chicago, Chicago, IL. He is a Fellow of the Acoustical Society of America and a past president of the Association for Research in Otolaryngology. His research focus is on the electromechanics of hearing.

This session was moderated by ARO President-Elect, Dr. John Oghalai.

When: Thursday, September 17th at 5PM CT

Click here to view the webinar recording Click here to view the presentation slides 

 

A special thank you to the ARO Virtual Learning Taskforce for organizing this exciting ARO initiative!

 

I began studying the vestibular system during my dissertation research at the Università di Pavia with Professors Ivo Prigioni and GianCarlo Russo. I had two postdoctoral fellowships, first at the University of Rochester with Professor Christopher Holt and then at the University of Illinois at Chicago with Professors Jonathan Art and Jay Goldberg.

My research focuses on characterizing the biophysics of synaptic transmission between hair cells and primary afferents in the vestibular system. For many years an outstanding question in vestibular physiology was how the transduction current in the type I hair cell was sufficient, in the face of large conductances on at rest, to depolarize it to potentials necessary for conventional synaptic transmission with its unique afferent calyx.

In collaboration with Dr. Art, I overcame the technical challenges of simultaneously recording from type I hair cells and their enveloping calyx afferent to investigate this question. I was able to show that with depolarization of either hair cell or afferent, potassium ions accumulating in the cleft depolarize the synaptic partner. Conclusions from these studies are that due to the extended apposition between type I hair cell and its afferent, there are three modes of communication across the synapse. The slowest mode of transmission reflects the dynamic changes in potassium ion concentration in the cleft which follow the integral of the ongoing hair cell transduction current. The intermediate mode of transmission is indirectly a result of this potassium elevation which serves as the mechanism by which the hair cell potential is depolarized to levels necessary for calcium influx and the vesicle fusion typical of glutamatergic quanta. This increase in potassium concentration also depolarizes the afferent to potentials that allow the quantal EPSPs to trigger action potentials. The third and most rapid mode of transmission like the slow mode of transmission is bidirectional, and a current flowing out of either hair cell or afferent into the synaptic cleft will divide between a fraction flowing out into the bath, and a fraction flowing across the cleft into its synaptic partner.

The technical achievement of the dual electrode approach has enabled us to identify new facets of vestibular end organ synaptic physiology that in turn raise new questions and challenges for our field. I look forward with great excitement to the next chapter in my scientific story.

 

Charles C. Della Santina, PhD MD is a Professor of Otolaryngology – Head & Neck Surgery and Biomedical Engineering at the Johns Hopkins University School of Medicine, where he directs the Johns Hopkins Cochlear Implant Center and the Johns Hopkins Vestibular NeuroEngineering Laboratory.

As a practicing neurotologic surgeon, Dr. Della Santina specializes in treatment of middle ear, inner ear and auditory/vestibular nerve disorders. His clinical interests include restoration of hearing via cochlear implantation and management of patients who suffer from vestibular disorders, with a particular focus on helping individuals disabled by chronic postural instability and unsteady vision after bilateral loss of vestibular sensation. His laboratory’s research centers on basic and applied research supporting development of vestibular implants, which are medical devices intended to partially restore inner ear sensation of head movement. In addition to that work, his >90 publications include studies characterizing inner ear physiology and anatomy; describing novel clinical tests of vestibular function; and clarifying the effects of cochlear implantation, vestibular implantation, superior canal dehiscence syndrome and intratympanic gentamicin therapy on the inner ear and central nervous system.  Dr. Della Santina is also the founder and CEO/Chief Scientific Officer of Labyrinth Devices LLC, a company dedicated to bringing novel vestibular testing and implant technology into routine clinical care.

Andrew Griffith received his MD and PhD in Molecular Biophysics and Biochemistry from Yale University in 1992. He completed his general surgery internship and a residency in Otolaryngology-Head and Neck Surgery at the University of Michigan in 1998. He also completed a postdoctoral research fellowship in the Department of Human Genetics as part of his training at the University of Michigan. In 1998, he joined the Division of Intramural Research (DIR) in the National Institute on Deafness and Other Communication Disorders (NIDCD). He served as a senior investigator, the chief of the Molecular Biology and Genetics Section, the chief of the Otolaryngology Branch, and the director of the DIR, as well as the deputy director for Intramural Clinical Research across the NIH Intramural Research Program. His research program identifies and characterizes molecular and cellular mechanisms of normal and disordered hearing and balance in humans and mouse models. Two primary interests of his program have been hearing loss associated with enlargement of the vestibular aqueduct, and the function of TMC genes and proteins. The latter work lead to the discovery that the deafness gene product TMC1 is a component of the hair cell sensory transduction channel. Since July of 2020, he has served as the Senior Associate Dean of Research and a Professor of Otolaryngology and Physiology in the College of Medicine at the University of Tennessee Health Science Center.

Gwenaëlle S. G. Géléoc obtained a PhD in Sensory Neurobiology from the University of Sciences in Montpellier (France) in 1996. She performed part of her PhD training at the University of Sussex, UK where she characterized sensory transduction in vestibular hair cells and a performed a comparative study between vestibular and cochlear hair cells. Gwenaelle continued her training as an electrophysiologist at University College London studying outer hair cell motility and at Harvard Medical School studying modulation of mechanotransduction in vestibular hair cells. As an independent investigator at the University of Virginia, she expanded this work and characterized the developmental acquisition of sensory transduction in mouse vestibular hair cells, the developmental acquisition of voltage-sensitive conductances in vestibular hair cells and the tonotopic gradient in the acquisition of sensory transduction in the mouse cochlea. This work along with quantitative spatio-temporal studies performed on several hair cell mechanotransduction candidates lead her to TMC1 and 2 and long-term collaborations with Andrew Griffith and Jeff Holt. Dr. Géléoc is currently Assistant Professor of Otolaryngology, at Boston Children’s Hospital where she continues to study molecular players involved in the development and function of hair cells of the inner ear and develops new therapies for the treatment of deafness and balance, with a particular focus on Usher syndrome.

Jeff Holt earned a doctorate from the Department of Physiology at the University of Rochester in 1995 for his studies of inward rectifier potassium channels in saccular hair cells.  He went on to a post-doctoral position in the Neurobiology Department at Harvard Medical School and the Howard Hughes Medical Institute, where he characterized sensory transduction and adaptation in hair cells and developed a viral vector system to transfect cultured hair cells.  Dr. Holt’s first faculty position was in the Neuroscience Department at the University of Virginia.  In 2011 the lab moved to Boston Children’s Hospital / Harvard Medical School.  Dr. Holt is currently a Professor in the Departments of Otolaryngology and Neurology in the F.M. Kirby Neurobiology Center.  Dr. Holt and his team have been studying sensory transduction in auditory and vestibular hair cells over the past 20 years, with particular focus on TMC1 and TMC2 over the past 12 years.  This work lead to the discovery that TMC1 forms the hair cell transduction channel.  His work also focuses on development gene therapy strategies for genetic hearing loss.