Frequency-intensity characteristics of cricket cercal interneurons: low-frequency-sensitive units


V. Y. Vedenina (1), G. I. Rozhkova (1), A. K. Panjutin (1), A. L. Byzov (1), G. Kamper (2)

1) Institute for Problems in Information Transmission, Russian Academy of Sciences, B. Karetnyi per. 19, 10447 Moscow, Russia
2) Abteilung Vergleichende Neurobiologie, Universitat Ulm, D-89069 Ulm, Germany e-mail: guenter.kaemper@biologie.uni-ulm.de Fax: +49-731-502-2629


Abstract:


Abstract
Three identified interneurons of the cercal system were investigated electrophysiologically; these interneurons are sensitive only to stimulation of cercal filiform-hair sensilla by low-frequency sound. Measurement of the frequency ranges revealed cut-off frequencies between ca. 20 and 70 Hz. Analysis of the responses near threshold and at higher intensities in the frequency range 5-500 Hz shows that one of them (Interneuron 9-1b) exhibits a sensitivity maximum at the frequency-intensity combination necessary for the perception of an intraspecific signal at 30 Hz. This band-pass behavior disappears at higher stimulus intensities. In order to investigate the mechanism of the low-frequency selectivity of the interneurons, two-tone stimulation experiments were performed. When stimuli in the best-frequency range were superimposed by a 100-Hz tone, the spiking activity was suppressed in an intensity-dependent manner.


Key words:

Sensory systems Acheta domesticus Neural filter Air-particle oscillation Low-pass