Frequency tuning of the dolphin’s hearing as revealed by auditory brain-stem response with notch-noise masking

Abstract

Notch-noise masking was used to measure frequency tuning in a dolphin (Tursiops truncatus) in a simultaneous-masking paradigm in conjunction with auditory brain-stem evoked potential recording. Measurements were made at probe frequencies of 64, 76, 90, and 108 kHz. The data were analyzed by fitting the rounded-exponent model of the auditory filters to the experimental data. The fitting parameter values corresponded to the filter tuning as follows: QER (center frequency divided by equivalent rectangular bandwidths) of 35 to 36.5 and Q10 dB of 18 to 19 at all tested frequencies.

Hearing in Cetaceans: From Natural History to Experimental Biology

“…Because there is a uniform distribution of hair cells on the BM, but not 5 uniform displacement (i.e., lower frequencies have longer wavelengths, and thus displace a 6 larger surface area of the BM) more hair cells are allocated to lower frequencies resulting in finer 7 frequency resolution. 8 Frequency selectivity has been measured in odontocetes using both electrophysiological 9 (Popov, et al, 1997) ( 1) 5 where ΔF CB is the CB and K is a constant. If K is assumed to equal to 1, the equation simplifies 6 to: 7…”

Marine Mammals and Low-frequency Sound: Progress Since 1994

“…Several papers have appeared since 1994 reporting on use of auditory evoked potentials to study dolphins (Szymanski et al, 1995(Szymanski et al, ,1998Popov and Klishin, 1998;Popov and Supin, 1998;Popov et al, 1998). Dolphin (1997) reviewed auditory processing in several toothed whales (Grampus, Orcinus, Tursiops, Delphinapterus) that were studied using evoked potential methods.…”

“…Some thresholds for killer whales and dolphins have been obtained using evoked potential methods (Popov and Supin, 1998;Popov and Klishin, 1998;Popov et al, 1998;Szymanski et al, 1995Szymanski et al, ,1996Szymanski et al, ,1998, but further research on methods of evoked potential audiometry are required for the application of the SWAT team approach to large whales.…”

“…Ridgway and Au (1999) reviewed earlier work on processing by the auditory central nervous system and approaches to sound conduction to the dolphin ear. Popov and Supin (1998) studied dolphin auditory evoked responses to rhythmic sound pulses. Popov and Klishin (1998) reported on a study of common dolphin hearing using the electroencephalogram.…”

“…Popov and Supin (1998) studied dolphin auditory evoked responses to rhythmic sound pulses. Popov and Klishin (1998) reported on a study of common dolphin hearing using the electroencephalogram. Popov et al (1998) reported on frequency tuning of the dolphin auditory system using evoked potential methods.…”