Peripheral auditory processing in the bobtail lizard Tiliqua rugosa
- 51 Downloads
Primary auditory-nerve fibres of the bobtail lizard have asymmetrical, V-shaped frequency-threshold tuning curves. Fibre characteristic frequencies (CF) ranged from 0.2 to 4.5 kHz. The most sensitive fibres had a CF near 1.2 kHz and a threshold of 6 dB SPL.
Fibres with CFs below 0.85 kHz had simple U-shaped tuning curves; higher-CF fibres had tuning curves with obvious sharp tips around CF. These tips were up to 46 dB in depth. Several other parameters of the tuning curves, like the selectivity coefficients Q10 dB and Q40 dB and the course of the tuning curve flanks, also permit a separation into the same low-CF and high-CF groups.
The tuning sharpness and the thresholds of both low- and high-CF fibres were hypoxia-sensitive, the loss of sensitivity being greatest at CF.
Only the low-CF group of fibres showed two-tone rate suppression. In those fibres, two-tone rate suppression was only found with suppressor frequencies above CF, but not below CF.
Key wordsLizard Hearing Auditory nerve Frequency tuning
two-tone rate suppression
Unable to display preview. Download preview PDF.