Conditioned frequency-dependent hearing sensitivity reduction in the bottlenose dolphin (<i>Tursiops truncatus</i>)

Nachtigall, Paul E.; Supin, Alexander Ya.

doi:10.1242/jeb.114066

Cited by 14 publications

(12 citation statements)

References 35 publications

(39 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The quickness of this change may be explained by the fact that this animal was not naive to the hearing dampening experimental protocol and conditioning for hearing change occurs very rapidly. This dolphin had previously been exposed to warnings and loud sounds (Nachtigall and Supin, 2015) and had previously shown learned hearing sensation changes. Other work with a totally naive beluga whale (Nachtigall et al, 2016) demonstrated that the conditioning process for hearing change occurs very rapidlywithin a 36 trial session.…”

Section: Discussionmentioning

confidence: 99%

“…1 µPa, which was higher than typical of bottlenose dolphins recently wild-caught and higher than in-captivity bottlenose dolphins and other odontocete species (Au and Hastings, 2008), which were generally between 50 and 70 dB. However, her hearing was considered as still suitable for this investigation of basic hearing change processes (Nachtigall and Supin, 2015). The subject was housed in a floating pen complex off of Coconut Island in Kaneohe Bay.…”

Section: Materials and Methods Experimental Facilities And Subjectmentioning

confidence: 99%

“…Given that ability to change hearing sensitivity, it also seemed reasonable to test whether the false killer whale, the bottlenose dolphin , 2015 and the beluga whale (Nachtigall et al, 2016) would likewise dampen hearing when signaled that a loud sound was about to arrive. All of these odontocetes changed their hearing sensitivity when a warning signal preceded the arrival of a relatively loud sound, thereby mitigating its effects.…”

Section: Introductionmentioning

confidence: 99%

“…Much previous work (e.g. Nachtigall and Supin, 2013, 2015 assumed that sensitive measures of hearing change required a random variation of the warning signal. This effort provided a test of that assumption.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Expectancy and conditioned hearing levels in the bottlenose dolphin (Tursiops truncatus)

Nachtigall

Supin

Smith

et al. 2016

Journal of Experimental Biology

Self Cite

View full text Add to dashboard Cite

The hearing sensitivity of a bottlenose dolphin for a warning sound, when the exact time of the arrival of a loud sound could or could not be predicted, was measured. Sensitivity was measured when the time of onset of the loud sound was randomly varied (random-variation sessions) and when the time of onset of the loud sound and the pattern of stimulus levels was constant (fixed-stimulus sessions). The loud sound was kept the same in both of the series. The mean duration and mean range of the levels of the test/warning signal were also kept equal across experimental sessions. Hearing sensitivity was measured using the auditory evoked potential method with rhythmic trains of short pips as test stimuli. With randomly varied warning sounds, thresholds before the loud sound were on average 10.6 dB higher than the baseline thresholds. With fixed warning signals, thresholds were on average 4.4 dB higher than the baseline thresholds. Considering that the loud sounds were identical, the difference between the random-variation and the fixed-stimulus sessions cannot be explained by a direct (unconditioned) influence of sound exposure. Therefore, the data provide reliable evidence for the conditioning nature of the hearing-dampening effect and also demonstrate that hearing sensitivity change also depends on when the animal can expect the loud sound to occur.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Materials and Methods Experimental Facilities And Subjectmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Expectancy and conditioned hearing levels in the bottlenose dolphin (Tursiops truncatus)

Nachtigall

Supin

Smith

et al. 2016

Journal of Experimental Biology

Self Cite

View full text Add to dashboard Cite

show abstract

“…However, to what extent middle ear mechanisms such as the stapedial reflex in the case of bats, contribute to the development in hearing sensitivity following a loud emitted broadband click remains an open question (Nachtigall and Supin, 2015). Since forward masking is only acting on the auditory neurons rendered refractory by the previous stimulus, it is a highly frequency-specific phenomenon related to the width of the auditory filters and the spectra of the sound stimuli used (Popov et al 2001).…”

Section: Introductionmentioning

confidence: 99%

Time varying auditory gain control in response to double pulse stimuli in harbour porpoises is not mediated by a stapedial reflex

2017

View full text Add to dashboard Cite

Echolocating animals reduce their output level and hearing sensitivity with decreasing echo delays, presumably to stabilize the perceived echo intensity during target approaches. In bats, this variation in hearing sensitivity is formed by a call-induced stapedial reflex that tapers off over time after the call. Here, we test the hypothesis that a similar mechanism exists in toothed whales by subjecting a trained harbour porpoise to a series of double sound pulses varying in delay and frequency, while measuring the magnitudes of the evoked auditory brainstem responses (ABRs). We find that the recovery of the ABR to the second pulse is frequency dependent, and that a stapedial reflex therefore cannot account for the reduced hearing sensitivity at short pulse delays. We propose that toothed whale auditory time-varying gain control during echolocation is not enabled by the middle ear as in bats, but rather by frequency-dependent mechanisms such as forward masking and perhaps higher-order control of efferent feedback to the outer hair cells.

show abstract

Ecomorphology of toothed whales (Cetacea, Odontoceti) as revealed by 3D skull geometry

et al. 2023

View full text Add to dashboard Cite

Extant odontocetes (toothed whales) exhibit differences in body size and brain mass, biosonar mode, feeding strategies, and diving and habitat adaptations. Strong selective pressures associated with these factors have likely contributed to the morphological diversification of their skull. Here, we used 3D landmark geometric morphometric data from the skulls of 60 out of ~ 72 extant odontocete species and a well-supported phylogenetic tree to test whether size and shape variation are associated with ecological adaptations at an interspecific scale. Odontocete skull morphology exhibited a significant phylogenetic signal, with skull size showing stronger signal than shape. After accounting for phylogeny, significant associations were detected between skull size and biosonar mode, body length, brain and body mass, maximum and minimum prey size, and maximum peak frequency. Brain mass was also strongly correlated with skull shape together with surface temperature and average and minimum prey size. When asymmetric and symmetric components of shape were analysed separately, a significant correlation was detected between sea surface temperature and both symmetric and asymmetric components of skull shape, and between diving ecology and the asymmetric component. Skull shape variation of odontocetes was strongly influenced by evolutionary allometry but most of the associations with ecological variables were not supported after phylogenetic correction. This suggests that ecomorphological feeding adaptations vary more between, rather than within, odontocete families, and functional anatomical patterns across odontocete clades are canalised by size constraints.

show abstract

Conditioned frequency-dependent hearing sensitivity reduction in the bottlenose dolphin (Tursiops truncatus)

Cited by 14 publications

References 35 publications

Expectancy and conditioned hearing levels in the bottlenose dolphin (Tursiops truncatus)

Expectancy and conditioned hearing levels in the bottlenose dolphin (Tursiops truncatus)

Time varying auditory gain control in response to double pulse stimuli in harbour porpoises is not mediated by a stapedial reflex

Ecomorphology of toothed whales (Cetacea, Odontoceti) as revealed by 3D skull geometry

Contact Info

Product

Resources

About