02386nas a2200229   4500008004100000245010400041210006900145520161400214653001401828653001001842653002201852653002901874653002201903653000901925100001701934700001801951700002301969700001401992700001602006700001402022856012002036       2013                        eng d00aMechanical tuning of the moth ear: distortion-product otoacoustic emissions and tympanal vibrations0 aMechanical tuning of the moth ear distortionproduct otoacoustic 3 a<p>The mechanical tuning of the ear in the moth Empyreuma pugione was investigated by distortion-product otoacoustic emissions (DPOAE) and laser Doppler vibrometry (LDV). DPOAE audiograms were assessed using a novel protocol that may be advantageous for non-invasive auditory studies in insects. To evoke DPOAE, two-tone stimuli within frequency and level ranges that generated a large matrix of values (960 frequency&ndash;level combinations) were used to examine the acoustic space in which the moth tympanum shows its best mechanical and acoustical responses. The DPOAE tuning curve derived from the response matrix resembles that obtained previously by electrophysiology, and is V-shaped and tuned to frequencies between 25 and 45 kHz with low Q10dB values of 1.21&plusmn;0.26. In addition, while using a comparable stimulation regime, mechanical distortion in the displacement of the moth&rsquo;s tympanal membrane at the stigma was recorded with a laser Doppler vibrometer. The corresponding mechanical vibration audiograms were compared with DPOAE audiograms. Both types of audiograms have comparable shape, but most of the mechanical response fields are shifted towards lower frequencies. We showed for the first time in moths that DPOAE have a pronounced analogy in the vibration of the tympanic membrane where they may originate. Our work supports previous studies that point to the stigma (and the internally associated transduction machinery) as an important place of sound amplification in the&nbsp;moth ear, but also suggests a complex mechanical role for the rest of the transparent zone.</p>
10aAudiogram10aDPOAE10aEmpyreuma pugione10alaser Doppler vibrometry10amechanical tuning10amoth1 aMora, E., C.1 aCobo-Cuan, A.1 aMacias-Escriva, F.1 aPerez, M.1 aNowotny, M.1 aKossl, M.  uhttp://jeb.biologists.org/cgi/doi/10.1242/jeb.085902https://syndication.highwire.org/content/doi/10.1242/jeb.08590202386nas a2200193   4500008004100000245009800041210006900139520176800208653001901976653001201995653002902007653002202036653001302058653001902071100001502090700001402105700001602119856005702135       2011                        eng d00aSound-induced tympanal membrane motion in bushcrickets and its relationship to sensory output0 aSoundinduced tympanal membrane motion in bushcrickets and its re3 a<p>n the auditory system of bushcrickets, sound can reach the receptors via two different paths: (i) by acting on the outside of the tympana situated on both sides of each foreleg or (ii) through the acoustic trachea that opens at a spiracle on the thorax. While the spiracle is considered to be the main point of sound entry for higher audio and ultrasonic frequencies, the role of the tympana is still unclear. The tympana border the air-filled acoustic trachea as well as the fluid-filled haemolymph channel containing the receptor organs. To understand their role during sound transduction, the sound-induced neuronal response of the hearing organ was recorded in combination with measurement of tympanal membrane motion using laser-Doppler vibrometry. For far-field stimulation, the frequency of the most sensitive hearing (&sim;16 kHz) matched the frequency of a pronounced maximum of tympanal membrane vibration. A second maximum of tympanum motion at lower frequencies (&sim;7 kHz) was correlated with an increased nerve activity at higher intensities (&gt;70 dB sound pressure level, SPL). These correlations support the hypothesis of functional coupling between tympanum motion and nerve activity. When sound stimuli were applied locally, through either the tympanum or the spiracle, significant differences between tympanum motion and nerve activity were found. These discrepancies show that tympanum motion and neuronal response are not coupled directly and that there is no linear relationship with the applied SPL. Taken together, these data verify a functional, albeit indirect, coupling of tympanum motion and sensory cell activity for one of the pronounced vibration maxima, which appears to represent a resonance frequency of the tympanum.</p>
10ainsect hearing10akatydid10alaser-Doppler vibrometer10aMecopoda elongata10aspiracle10atympanal nerve1 aHummel, J.1 aKossl, M.1 aNowotny, M.  uhttp://jeb.biologists.org/cgi/doi/10.1242/jeb.054445