Cochlear physiology and ultrastucture

A prominent area of my research concerns the physiology of the sensory receptor cells (the hair cells) of the mammalian hearing organ (the cochlea) and how they communicate with the sensory neurons of the spiral ganglion at specialized synapses. To overcome the practical difficulties in gaining access to this system, we have developed a procedure to isolate the inner ear from the skull and maintain it in short-term culture. The use of the intact hearing organ is necessary to preserve the synaptic connections. Experiments using fluorescent indicators of intracellular sodium and calcium have recently shown how hair cell homeostasis can be maintained in vitro. Biophysical modeling has been used to understand how experimental artifacts and culture conditions affect hair cell function, including their responses to stimuli.

e-mail Dr. Siegel
ph: 847.491.2454
fax: 847.491.2523

Selected References:

• Siegel J.H., Cerka A.J., Recio-Spinoso A. et al. (2005). Delays of stimulus-frequency otoacoustic emissions and cochlear vibrations contradict the theory of coherent reflection filtering. Journal of the Acoustical Society of America 118: 2434-2443.

• Dreisbach L.E., Siegel J.H. (2005). Level dependence of distortion-product otoacoustic emissions measured at high frequencies in humans. Journal of the Acoustical Society of America 117: 2980-2988.

• Zeddies D.G., Siegel J.H. (2004). A biophysical model of an inner ear cell. Journal of the Acoustical Society of America 116: 426-441.

• Dreisbach L.E., Siegel J.H. (2001). Distortion-product otoacoustic emissions measured at high frequencies in humans. Journal of the Acoustical Society of America 110: 2456-2469.

• Ohlemiller K.K. and Siegel J.H. (1998) Temporal aspects of cooling on responses of single auditory nerve fibers. Hearing Research 123: 78-86.

Other Links:

• Northwestern University School of Speech