Independent Group Leader
Mechanisms of Auditory Perception
Phone: +49 69/ 798 42063
Sensitive Hearing – Mechanisms Related to Acoustic Signal Transduction
1) Basics of Peripheral Hearing
The first step in the hearing process is the conversion of sound waves into a movement of a structure, such as a membrane or sensory cells. This leads to the opening of mechano-sensitive ion channels in the sensory cells of the hearing organ. The resulting ion inflow changes the membrane potential of the neuronal cell, which can be transmitted to higher centers as a signal (action potential). This process is called mechano-electrical transduction (MET). Although MET is a fundamental process in hearing and can be found in all parts of the animal kingdom, it is still not understood in detail.
Using laser-Doppler-vibrometry measurements and physiological records we study the mechano-electrical transduction in a simple hearing organ of bushcrickets, called crista acustica. One of the most exciting moments of the project was when we realized that bushcrickets use travelling waves for frequency discrimination (Palghat Udayashankar et al. 2012 and see movie). These waves are comparable (wave propagation velocity and wave length) to travelling waves found in mammals. Electrophysiological measurements confirm the main sound enters through a spiracle in the prothorax and show that the tympanum motion is not directly coupled to the electrical response of the sensory cells (Hummel et al., 2011).
The project is funded by the Deutsche Forschungsgemeinschaft (NO 841/1-1 and NO 841/2-1). Additional funding is provided by the Jürgen Manchot foundation and Goethe University by the project "Nachwuchswissenschaftler/innen im Fokus"
On the link below you can download a small video file where you can see an animated wave. Click the right Mousebutton and choose "Save Link as...." to download the videofile.
2) Inner Ear Damages and the Generation of Tinnitus
The emergence of tinnitus after acoustic overstimulation and damage to the inner ear is an enormous psychological burden for patients. Exact causes of the resulting phantom noise are largely unknown. We suspect one reason for the initiation of the development of tinnitus in the signal transduction process and routing in the inner ear. We would like to understand which factors are critical and what drives the development of tinnitus to explain the observation that some animals develop tinnitus and others do not, despite all were exposed to the same damaging stimulus. Our experiments include the examination of the shift from acute to chronic tinnitus after acoustic overstimulation by using the startle reflex response in gerbils, which was successfully established as animal model for tinnitus detection (Nowotny et al. 2011).
The project is funded by the Deutsche Forschungsgemeinschaft (NO 841/4-1) and the Adolf-Messer Stiftungspreis 2009.
Awards and Publications
Attempto Award 2007
The Attempto Award has been presented to young researchers for excellent work in the field of neurobiology.
Adolf Messer-Stiftungspreis 2009
The Award of the Adolf Messer-Foundation is given for foward-looking projects of basic research in natural and medical science.
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Steube N, Nowotny M, Pilz PK, Gaese BH. Dependence of the Startle Response on Temporal and Spectral Characteristics of Acoustic Modulatory Influences in Rats and Gerbils. Front Behav Neurosci. 2016 Jun 30;10:133. doi: 10.3389/fnbeh.2016.00133. eCollection 2016.
Hummel J, Schöneich S, Hedwig B, Nowotny M. (2014). Mechanical and electrical tuning in a tonotopical organized ear. In: Mechanics of Hearing. Corey D.P. and Karavitaki K.D. (Eds.). World Scientific, Singapore, New Jersey, London, Hong Kong, in press.
Nowotny M., Hummel J., Kössl M., Palgath Udajashankar A. (2014). Mechanical investigations of sound-induced responses in a simple ear. In: Mechanics of Hearing. Corey D.P. and Karavitaki K.D. (Eds.). World Scientific, Singapore, New Jersey, London, Hong Kong. in press.
Palgath Udajashankar A., Kössl M., Nowotny M. (2014). Traveling wave energy is lateralized in the hearing organ of bushcrickets. Plos One 9(1): e86090.
Möckel D., Nowotny M., Kössl M. (2014). Mechanical basis of otoacoustic emissions in tympanal hearing organs. J Comp Physiol A Neuroethol Sens Neural Behav Physiol. 200(7):681-691.
Möckel, D.; Lang, J.; Kössl, M. Nowotny, M. (2012). Temperature-dependence of DPOAEs in tympanal organs. J Exp Biol accepted.
Nowotny M.; Remus M.; Kössl M.; Gaese B.H. (2011). Characterization of the Perceived Sound of Trauma-Induced Tinnitus in Gerbils. J Acoust Soc Am 130(5): 2827-2834.
Nowotny M.; Weber M.; Palghat Udayashankar A.; Hummel J.; Kössl M. (2011). Sound Transduction in the Auditory System of Bushcrickets. In: Mechanics of Hearing. Shera C. and Olson E. (Eds.). World Scientific, Singapore, New Jersey, London, Hong Kong, pp. 461-465.Fleischer M.; Harasztosi C.; Nowotny M.; Zahnert T.; Gummer A.W. (2011). Continuum Mechanical Model of the Outer Hair Cell. In: Mechanics of Hearing. Shera C. and Olson E. (Eds.). World Scientific, Singapore, New Jersey, London, Hong Kong, pp. 160-165.
Nowotny, M.; Gummer, A.W. (2006). Nanomechanics of the subtectorial space caused by electromechanics of cochlear outer hair cells. Proc Natl Acad Sci USA 103: 2120-2125.
Scherer, M. P.; Nowotny, M.; Dalhoff, E.; Zenner, H. P.; Gummer, A. W. (2003). High-frequency vibration of the organ of Corti in vitro.
|2000||Martin T.; Nowotny M. (2000). The docodont Haldanodon from the Guimarota mine.- In: Martin T & Krebs B (eds.) Guimarota , a Jurassic Ecosystem. Pfeil Verlag. München.|