title: Source-to-sensation level ratio of transmitted biosonar pulses in an echolocating false killer whale.
abstract: Transmitted biosonar pulses, and the brain auditory evoked potentials (AEPs) associated with those pulses, were synchronously recorded in a false killer whale Pseudorca crassidens trained to accept suction-cup EEG electrodes and to detect targets by echolocation. AEP amplitude was investigated as a function of the transmitted biosonar pulse source level. For that, a few thousand of the individual AEP records were sorted according to the spontaneously varied amplitude of synchronously recorded biosonar pulses. In each of the sorting bins (in 5-dB steps) AEP records were averaged to extract AEP from noise; AEP amplitude was plotted as a function of the biosonar pulse source level. For comparison, AEPs were recorded to external (in free field) sound pulses of a waveform and spectrum similar to those of the biosonar pulses; amplitude of these AEPs was plotted as a function of sound pressure level. A comparison of these two functions has shown that, depending on the presence or absence of a target, the sensitivity of the whale's hearing to its own transmitted biosonar pulses was 30 to 45 dB lower than might be expected in a free acoustic field.
authors.affiliation: Institute of Ecology and Evolution of the Russian Academy of Sciences, 33 Leninsky Prospect, 119071 Moscow, Russia. alex_supin@sevin.ru
authors.forename: Alexander Ya
authors.initials: AY
authors.lastname: Supin
authors.forename: Paul E
authors.initials: PE
authors.lastname: Nachtigall
authors.forename: Marlee
authors.initials: M
authors.lastname: Breese
mesh_terms: D000162:Acoustics; D000818:Animals; D004289:Dolphins / Q000502:physiology*; D004455:Echolocation / Q000502:physiology*; D004569:Electroencephalography / Q000662:veterinary; D005072:Evoked Potentials, Auditory / Q000502:physiology; D005260:Female; D011897:Random Allocation