Experimental investigation of mechano-electrical signal transduction in a simple auditory organ [in the hearing organ of bushcrickets]

• Applicant: Professorin Dr. Manuela Nowotny
• Subject Area: Cognitive, Systems and Behavioural Neurobiology
• Term: from 2008 to 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 84231963

• Final Report Year: 2018

Final Report Abstract

Hearing organs open up the physical world of sound waves to us. Due to the structures of the respective hearing organ, different frequency bandwidth can be perceived. We have investigated how different ears of insects, especially bushcrickets, are adapted to their behavioural-relevant communication frequencies. We were able to detect a sex-specific auditory fovea in the ears of male Ancylecha fenestrata and showed how in the ears of Mecopoda elongata the vibration of the tympana and hearing organ (crista acustica) corresponds to the generated vocal frequencies. In addition, we demonstrated that sound waves in bushcricket ears cause slow waves, so-called travelling waves, whose properties are similar to those in the inner ear of mammals. These waves are distributed tonotopically and generate enough force to open transduction channels by a phase delay of the organ motion. A comparison of mechanical and neuronal tuning curves, measured at the same position of the crista acustica, revealed that mechano-sensitive ion channels only open when this phase delay along the longitudinal organ axis is present. A simple up and down movement (without phase delay) does not open the ion channels. This indicates that not all stimulus-induced motions are converted into neuronal responses and that intrinsic factors within the sensory cells, such as the position of the mechano-sensitive ion channels near the cap, play an important role in mechanoelectrical transduction process. Our investigations have clarified the function of the processes that describe the conversion of sound signals into a neuronal response in the sensory cells of the ear in living animals.

Publications

• 2010. Acoustic-induced motion of the bushcricket (Mecopoda elongata, Tettigoniidae) tympanum. J Comp Physiol A 196: 939-945
  Nowotny M, Hummel J, Weber M, Möckel D, 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
  Nowotny M.; Weber M.; Palghat Udayashankar A.; Hummel J.; Kössl M.
  
• 2011. Sound-induced tympanal membrane motion in bushcrickets and its relation to the sensory output. J Exp Biol. 214: 3596-3604
  Hummel J, Kössl M, Nowotny M
  
• 2011. Tonotopically ordered traveling waves in the hearing organs of bushcrickets in-vivo. In: Mechanics of Hearing. Shera C. and Olson E. (Eds.). World Scientific, Singapore, New Jersey, London, Hong Kong, pp. 466-472
  Palghat Udayashankar A.; Kössl M.; Nowotny M.
  
• 2012. In-vivo measurements of tonotopically ordered traveling waves. PLoS One. 7(2): e31008
  Palghat Udayashankar A, Kössl M, Nowotny M
  
• 2012. Temperature-dependence of DPOAEs in tympanal organs. J Exp Biol. 215:3309-3316
  Möckel D, Lang J, Kössl M, Nowotny M
  
• 2013. Mechanical tuning of the moth ear: distortion-product otoacoustic emissions and tympanal vibrations. J Exp Biol.216:3863-3872
  Mora E C, Cobo-Cuan A, Macías F, Pérez M, Nowotny M, Kössl M
  
• 2014. Mechanical basis of otoacoustic emissions in tympanal hearing organs. J Comp Physiol A. 200(7):681-691
  Möckel D, Nowotny M, Kössl M
  
• 2014. Neural processing in the bushcricket auditory pathway. In: Topics of Acoustic Communication in Insects. Hedwig B (Ed.) Springer-Verlag, Berlin, Heidelberg. Volume 1, 2014, pp 143-166
  Stumpner A., Nowotny M.
  
• 2014. Processing of simple and complex acoustic signals in a tonotopically organized ear. Proc Biol Sci. 281(1796): 20141872
  Hummel J, Wolf K, Kössl M, Nowotny M
  
• 2014. Traveling wave energy is lateralized in the hearing organ of bushcrickets. Plos One 9(1): e86090
  Palgath Udajashankar A, Kössl M, Nowotny M
  
• 2016. Auditory fovea in the ear of a duetting katydid shows male-specific adaptation to the female call. Curr Biol. 26(23):R1222-R1223
  Scherberich J, Hummel J, Schöneich S, Nowotny M
  
• 2016. Gating of Acoustic Transducer Channels Is Shaped by Biomechanical Filter Processes. J Neurosci. 36(8):2377-2382
  Hummel J, Schöneich S, Kössl M, Scherberich J, Hedwig B, Prinz S, Nowotny M
  
• 2016. 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, AIP Conference Proceedings 1703, 100001
  Hummel J, Schöneich S, Hedwig B, Nowotny M
  
• 2016. 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. AIP Conference Proceedings 1703, 070008
  Nowotny M., Hummel J., Kössl M., Palgath Udajashankar A
  
• 2017. Functional basis of the sexual dimorphism in the auditory fovea of the duetting bushcricket Ancylecha fenestrata. Proc Biol Sci. 284(1865)
  Scherberich J, Hummel J, Schöneich S, Nowotny M
  
• 2017. Morphological basis for a tonotopic design of an insect ear. J Comp Neurol. 525(10):2443-2455
  Hummel J, Kössl M, Nowotny M