Presented by Sidney Strickland of behalf of A. James Hudspeth
B.S., New York Institute of Technology
Frequency Selectivity of Synaptic Exocytosis in Hair Cells of the Bullfrog’s Amphibian Papilla
I will read remarks prepared by Jim Hudspeth who unfortunately couldn’t be here today:
One of the most important aspects of our hearing is the ability to recognize the sources of sounds in our environment. In nature, there is an obvious selective advantage in being able to distinguish a prospective meal, perhaps a tasty pig rooting in the bush, from a potential predator such as a lion. With the development of human speech came the necessity to differentiate between speakers, which we can do even in a crowded environment. Still greater refinement underlies our capacity to make aesthetic distinctions between the various instruments in an orchestra. We can distinguish sounds of different origins by their content of particular frequencies or tones. A female voice has a higher range of frequencies than a male voice; a violin is pitched above a viola. And your ability to separate my voice from that of the prior speaker stems from a still finer judgment of the pitches characteristic of individual voices.
These discriminations commence in the cochlea of the inner ear, which functions like an inverse piano to decompose complex sounds into their tonal constituents. Each of the sensory cells in the cochlea is tuned to a specific frequency of stimulation and sends signals about that frequency along nerve fibers into the brain.
Investigating the flow of information from the sensory cells to the nerves, Suchit found for the first time that this interaction is also tuned to specific frequencies. In other words, the chemical synapses at which sensory cells communicate with nerve fibers themselves help us to discriminate sounds. This result, which represents the first demonstration of tuned synapses, will encourage a search for additional examples of the phenomenon in other parts of the nervous system.
Suchit has long had an interest in clinical medicine as well as research. He earlier worked on several medical problems and encouraged disadvantaged high school students to enter medical careers. He has served as executive director of the Weill Cornell Community Clinic, a voluntary organization that provides medical services to the indigent, and founded the Heart-to-Heart program that offers citywide screening for cardiac problems. As a student in the M.D.-Ph.D. program, he will now complete his clinical coursework. Thereafter, Suchit plans to enter into a clinical career, perhaps in radiology, in which his personal warmth and intellectual acuity will serve him well.