On Amherst College Week: Little hair cells in our ears play big roles in hearing and balance.
Josef Trapani, associate professor of biology, says understanding hair cells can help us fix them in the future.
Joe Trapani is an Associate Professor of Biology at Amherst College and is a faculty member in the Neuroscience Program. He is also an Associate faculty member of the Neuroscience and Behavior Program at UMass.
Joe received a B.S., M.S., and Ph.D. from the University of Connecticut and spent grad school studying the biophysical properties of potassium channels in the lab of Stephen J. Korn. From Connecticut, Joe traveled to Portland, Oregon for his postdoctoral research in the lab of Teresa Nicolson at the Vollum Institute and the Oregon Hearing Research Center at Oregon Health & Science University.
During his postdoc, Joe examined the electrical activity of hair cells and afferent neurons of the lateral line of intact larval zebrafish. His work focused on important questions related to sensory transduction in hair cells.
Current research in the Trapani lab continues to try to understand how external sensory stimuli are transformed into meaningful neuronal information.
How do we sense the world around us? One way is by detecting different forms of energy—like light and sound—via sensory receptors. In the auditory and vestibular systems, this job is performed by hair cells, specialized receptors that transform sensory information into electrical impulses that travel along neurons to the brain. Found in our ear, these receptors are critical for many everyday functions by detecting sound waves and vestibular information, such as gravity and acceleration. In fish, hair cells also form the lateral line system, which detects nearby water motion for schooling, mating, and detection of predators and prey.
My team is interested how hair cells encode sensory information into electrical codes that determine perception, behaviors, and reflexes. Using zebrafish, we perform electrical measurements from individual neurons connected to hair cells and also record high-speed videos during behaviors. When we examine the patterns of electrical impulses following stimulation of a zebrafish’s hair cells and make high-speed video recordings of the startle reflex, we learn how aspects of the encoded neuronal activity inform the subsequent behavior. Recently, we found that when intensity of a strong startle-inducing stimulus is increased, the time to initiate the reflex gets faster. We then uncovered that this relationship is likely due to the timing of the neuron’s first electrical impulse as it was correlated to the reflex’s start time.
Our findings are not surprising given how critical it is for animals to startle more and more quickly with the appearance of a larger and larger threat. By confirming our hypotheses in zebrafish, the neuroscience behind such mechanisms also helps us understand the implications for humans. After all, once we know how hair cells play a role in our senses of hearing and balance, we can learn how to fix them when they’re not working.