The effect of signal duration on the underwater hearing thresholds of two harbor seals (Phoca vitulina) for single tonal signals between 0.2 and 40 kHz.
J Acoust Soc Am
; 127(2): 1135-45, 2010 Feb.
Article
em En
| MEDLINE
| ID: mdl-20136234
ABSTRACT
The underwater hearing sensitivities of two 2-year-old female harbor seals were quantified in a pool built for acoustic research by using a behavioral psycho-acoustic technique. The animals were trained only to respond when they detected an acoustic signal ("go/no-go" response). Detection thresholds were obtained for pure tone signals (frequencies 0.2-40 kHz; durations 0.5-5000 ms, depending on the frequency; 59 frequency-duration combinations). Detection thresholds were quantified by varying the signal amplitude by the 1-up, 1-down staircase method, and were defined as the stimulus levels, resulting in a 50% detection rate. The hearing thresholds of the two seals were similar for all frequencies except for 40 kHz, for which the thresholds differed by, on average, 3.7 dB. There was an inverse relationship between the time constant (tau), derived from an exponential model of temporal integration, and the frequency [log(tau)=2.86-0.94 log(f);tau in ms and f in kHz]. Similarly, the thresholds increased when the pulse was shorter than approximately 780 cycles (independent of the frequency). For pulses shorter than the integration time, the thresholds increased by 9-16 dB per decade reduction in the duration or number of cycles in the pulse. The results of this study suggest that most published hearing thresholds
Texto completo:
1
Base de dados:
MEDLINE
Métodos Terapêuticos e Terapias MTCI:
Terapias_biologicas
/
Hidroterapia
Assunto principal:
Limiar Auditivo
/
Phoca
/
Meio Ambiente
/
Audição
Tipo de estudo:
Prognostic_studies
Idioma:
En
Revista:
J Acoust Soc Am
Ano de publicação:
2010
Tipo de documento:
Article
País de afiliação:
Holanda