Humans can detect eardrum vibrations as small as a picometer as well as those that are nearly a million times larger. This extraordinary ability is made possible by the cochlea, an elegant hydromechanical structure that works to separate sounds of different frequencies and maps them onto a different place on the sensory epithelium (cochlea). This frequency-place map within the cochlea is refined by specialized sensory cells that provide feedback forces to actively amplify local mechanical resonances. Key features of mammalian hearing arise from this feedback mechanism, including sharp frequency selectivity, sensitivity, large dynamic range, and nonlinearities; all of which have important consequences for encoding the subtleties of speech and music. In my lab we are interested in understanding the biophysical mechanisms by which the auditory periphery parses frequency and intensity information, and how these functions degrade with hearing loss. We approach these questions using two key techniques.
First, we study how the hydromechanical properties of the inner ear form the place-frequency map by using non-invasive measurements of inner ear physiology combined with mechanical modeling. Second, using whole-cell patch clamping techniques combined with neuroanatomy and modeling we study the biophysical processes underlying sensory signalling at the first synapse between cochlear sensory cells and the primary auditory neuron.
Spatial Gradients in the Size of Inner Hair Cell Ribbons Emerge Before the Onset of Hearing in Rats. J Assoc Res Otolaryngol. 2017 Mar 30. View in: PubMed
A biophysical model examining the role of low-voltage-activated potassium currents in shaping the responses of vestibular ganglion neurons. J Neurophysiol. 2016 Aug 1; 116(2):503-21. View in: PubMed
Stimulus-frequency otoacoustic emissions in human newborns. J Acoust Soc Am. 2015 Jan; 137(1):EL78. View in: PubMed
Exploiting Dual Otoacoustic Emission Sources. AIP Conf Proc. 2015; 1703. View in: PubMed
Measuring stimulus-frequency otoacoustic emissions using swept tones. J Acoust Soc Am. 2013 Jul; 134(1):356-68. View in: PubMed
Frequency selectivity in Old-World monkeys corroborates sharp cochlear tuning in humans. Proc Natl Acad Sci U S A. 2011 Oct 18; 108(42):17516-20. View in: PubMed
Level dependence of distortion product otoacoustic emission phase is attributed to component mixing. J Acoust Soc Am. 2011 May; 129(5):3123-33. View in: PubMed
Deviations from Scaling Symmetry in the Apical Half of the Human Cochlea. AIP Conf Proc. 2011; 1403:483-488. View in: PubMed
Otoacoustic Estimates of Cochlear Tuning: Testing Predictions in Macaque. AIP Conf Proc. 2011; 1403:286-292. View in: PubMed
Ion channels set spike timing regularity of mammalian vestibular afferent neurons. J Neurophysiol. 2010 Oct; 104(4):2034-51. View in: PubMed
Ion channels in mammalian vestibular afferents may set regularity of firing. J Exp Biol. 2008 Jun; 211(Pt 11):1764-74. View in: PubMed
Comparing stimulus-frequency otoacoustic emissions measured by compression, suppression, and spectral smoothing. J Acoust Soc Am. 2007 Dec; 122(6):3562-75. View in: PubMed
Near equivalence of human click-evoked and stimulus-frequency otoacoustic emissions. J Acoust Soc Am. 2007 Apr; 121(4):2097-110. View in: PubMed