title: Processing of simple and complex acoustic signals in a tonotopically organized ear.
abstract: Processing of complex signals in the hearing organ remains poorly understood. This paper aims to contribute to this topic by presenting investigations on the mechanical and neuronal response of the hearing organ of the tropical bushcricket species Mecopoda elongata to simple pure tone signals as well as to the conspecific song as a complex acoustic signal. The high-frequency hearing organ of bushcrickets, the crista acustica (CA), is tonotopically tuned to frequencies between about 4 and 70 kHz. Laser Doppler vibrometer measurements revealed a strong and dominant low-frequency-induced motion of the CA when stimulated with either pure tone or complex stimuli. Consequently, the high-frequency distal area of the CA is more strongly deflected by low-frequency-induced waves than by high-frequency-induced waves. This low-frequency dominance will have strong effects on the processing of complex signals. Therefore, we additionally studied the neuronal response of the CA to native and frequency-manipulated chirps. Again, we found a dominant influence of low-frequency components within the conspecific song, indicating that the mechanical vibration pattern highly determines the neuronal response of the sensory cells. Thus, we conclude that the encoding of communication signals is modulated by ear mechanics.
authors.affiliation: Institute of Cell Biology and Neuroscience, Goethe University, Max-von-Laue-Straße 13, 60438 Frankfurt am Main, Germany.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Hummel
authors.affiliation: Institute of Cell Biology and Neuroscience, Goethe University, Max-von-Laue-Straße 13, 60438 Frankfurt am Main, Germany.
authors.forename: Konstantin
authors.initials: K
authors.lastname: Wolf
authors.affiliation: Institute of Cell Biology and Neuroscience, Goethe University, Max-von-Laue-Straße 13, 60438 Frankfurt am Main, Germany.
authors.forename: Manfred
authors.initials: M
authors.lastname: Kössl
authors.affiliation: Institute of Cell Biology and Neuroscience, Goethe University, Max-von-Laue-Straße 13, 60438 Frankfurt am Main, Germany nowotny@bio.uni-frankfurt.de.
authors.forename: Manuela
authors.initials: M
authors.lastname: Nowotny
mesh_terms: D000161:Acoustic Stimulation; D000162:Acoustics; D000818:Animals; D004594:Electrophysiology; D005260:Female; D006135:Gryllidae / Q000502:physiology*; D006309:Hearing / Q000502:physiology*; D008297:Male; D011984:Sensory Receptor Cells / Q000502:physiology
keywords: Tettigoniidae; bushcricket; crista acustica; electrophysiology; insect hearing; laser Doppler vibrometry