title: Frequency tuning of hearing in the beluga whale: discrimination of rippled spectra.
abstract: Frequency tuning was measured in the beluga whale (Delphinapterus leucas) using rippled-noise test stimuli in conjunction with an auditory evoked potential (AEP) technique. The test stimulus was a 2-octave-wide rippled noise with frequency-proportional ripple spacing. The rippled-noise signal contained either a single reversal or rhythmic (1-kHz rate) reversals of the ripple phase. Single or rhythmic phase reversals evoked, respectively, a single auditory brainstem response (ABR) or a rhythmic AEP sequence-the envelope following response (EFR). The response was considered as an indication of resolvability of the ripple pattern. The rhythmic phase-reversal test with EFR recording revealed higher resolution than the single phase-reversal test with single ABR recording. The limit of ripple-pattern resolution with the single phase-reversal test ranged from 17 ripples per octave (rpo) at 32 kHz to 24 rpo at 45 to 64 kHz; for the rhythmic phase-reversal test, the limit ranged from 20 to 32 rpo. An interaction model of a ripple spectrum with frequency-tuned filters suggests that the ripple-pattern resolution limit of 20 to 32 rpo requires a filter quality Q of 29 to 46. Possible causes of disagreement of these estimates with several previously published data are discussed.
authors.affiliation: Institute of Ecology and Evolution, Russian Academy of Sciences, 33 Leninsky Prospect, 119071 Moscow, Russia.
authors.forename: Evgenia V
authors.initials: EV
authors.lastname: Sysueva
authors.affiliation: Institute of Ecology and Evolution, Russian Academy of Sciences, 33 Leninsky Prospect, 119071 Moscow, Russia.
authors.forename: Dmitry I
authors.initials: DI
authors.lastname: Nechaev
authors.affiliation: Institute of Ecology and Evolution, Russian Academy of Sciences, 33 Leninsky Prospect, 119071 Moscow, Russia.
authors.forename: Vladimir V
authors.initials: VV
authors.lastname: Popov
authors.affiliation: Institute of Ecology and Evolution, Russian Academy of Sciences, 33 Leninsky Prospect, 119071 Moscow, Russia.
authors.forename: Alexander Ya
authors.initials: AY
authors.lastname: Supin
mesh_terms: D000161:Acoustic Stimulation; D000162:Acoustics; D000818:Animals; D001301:Audiometry, Pure-Tone; D001306:Auditory Pathways / Q000502:physiology; D001309:Auditory Threshold; D050643:Beluga Whale / Q000502:physiology* / Q000523:psychology; D003463:Cues; D004192:Discrimination, Psychological; D016057:Evoked Potentials, Auditory, Brain Stem; D006309:Hearing; D008297:Male; D009038:Motion; D009622:Noise / Q000009:adverse effects; D010470:Perceptual Masking; D010897:Pitch Discrimination; D013016:Sound; D013018:Sound Spectrography; D013997:Time Factors