Radha Kalluri

Assistant Professor of Otolaryngology
Joint Apt. in Biomedical Engineering
University of Southern California

Research Topics

  1. cochlear mechanics, acoustics, nonlinear wave phenomena
  2. otoacoustic emissions and noninvasive testing of cochlear function
  3. sensory transduction in the auditory and vestibular periphery
  4. biophysics of sensory neurons

Research Overview

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.

Selected Publications

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Kalluri R, Monges-Hernandez M. (2017) Spatial Gradients in the Size of Inner Hair Cell Ribbons Emerge Before the Onset of Hearing in Rats. J Assoc Res Otolaryngol. 2017 Jun;18(3):399-413. doi: 10.1007/s10162-017-0620-1. -PubMed

Hight AE, Kalluri R. (2016) A biophysical model examining the role of low-voltage-activated potassium currents in shaping the responses of vestibular ganglion neurons. J Neurophysiol. 1;116(2):503-21. doi: 10.1152/jn.00107.2016.

Kalluri R, Xue J, Eatock RA. (2010) Ion channels set spike timing regularity of mammalian vestibular afferent neurons.J Neurophysiol. Oct;104(4):2034-51.  -PubMed

Kalluri R, Shera CA. (2013) Measuring stimulus-frequency otoacoustic emissions using swept tones. J Acoust Soc Am. 2013 Jul;134(1):356-68. doi: 10.1121/1.4807505.

Joris PX, Bergevin C, Kalluri R, Mc Laughlin M, Michelet P, van der Heijden M, Shera CA. (2011) Frequency selectivity in Old-World monkeys corroborates sharp cochlear tuning in humans. Proc Natl Acad Sci U S A. Oct 18;108(42):17516-20. -PubMed

Kalluri, R. and Shera, C.A. (2001) Distortion Product Source Unmixing: A test of the two-mechanism model for DPOAE generation. J. Acoust. Soc. Am. 109(2), 622 - 637. -PubMed