1
|
Branstetter BK, Sills JM. Mechanisms of auditory masking in marine mammals. Anim Cogn 2022; 25:1029-1047. [PMID: 36018474 PMCID: PMC9617968 DOI: 10.1007/s10071-022-01671-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 06/16/2022] [Accepted: 08/06/2022] [Indexed: 11/01/2022]
Abstract
Anthropogenic noise is an increasing threat to marine mammals that rely on sound for communication, navigation, detecting prey and predators, and finding mates. Auditory masking is one consequence of anthropogenic noise, the study of which is approached from multiple disciplines including field investigations of animal behavior, noise characterization from in-situ recordings, computational modeling of communication space, and hearing experiments conducted in the laboratory. This paper focuses on laboratory hearing experiments applying psychophysical methods, with an emphasis on the mechanisms that govern auditory masking. Topics include tone detection in simple, complex, and natural noise; mechanisms for comodulation masking release and other forms of release from masking; the role of temporal resolution in auditory masking; and energetic vs informational masking.
Collapse
Affiliation(s)
- Brian K Branstetter
- National Marine Mammal Foundation, 2240 Shelter Island Drive, #204, San Diego, CA, 92106, USA.
| | - Jillian M Sills
- Institute of Marine Sciences, Long Marine Laboratory, University of California Santa Cruz, Santa Cruz, CA, 95060, USA
| |
Collapse
|
2
|
Burkard R, Finneran JJ, Mulsow J. Comparison of maximum length sequence and randomized stimulation and averaging methods on the bottlenose dolphin auditory brainstem response. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2018; 144:308. [PMID: 30075678 DOI: 10.1121/1.5046069] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2018] [Accepted: 06/25/2018] [Indexed: 06/08/2023]
Abstract
The purpose of the present study was to compare auditory brainstem responses (ABRs) using two approaches that allow the use of high stimulation rates, but with different temporal variability in the interstimulus interval: maximum length sequences (MLS) and iterative randomized stimulation and averaging (I-RSA). ABRs were obtained to click stimuli in six bottlenose dolphins (Tursiops truncatus). In experiment 1, click level was held constant and click rate varied from 25 to 1250 Hz. For MLS, interstimulus intervals varied by a factor of 6 at each rate, while for I-RSA the interstimulus intervals varied by ± 0.5 ms regardless of rate. In experiment 2, stimulus rates ranged from 100 to 1000 Hz and click level varied from 105 to 135 dB re: 1 μPa. For experiment 1, MLS and I-RSA showed similar decreases in ABR peak amplitudes and increases in ABR peak latencies and interwave intervals with increasing rate. For experiment 2, there was an increase in peak latency and a decrease in peak amplitude with decreasing click level; however, the effects of click level were reduced at higher rates. The results indicate that the greater jitter for MLS compared to I-RSA does not substantially affect the dolphin ABR.
Collapse
Affiliation(s)
- Robert Burkard
- Department of Rehabilitation Science, University at Buffalo, 626 Kimball Tower, Buffalo, New York 14214, USA
| | - James J Finneran
- United States Navy Marine Mammal Program, Space and Naval Warfare Systems Center Pacific, Code 71510, 53560 Hull Street, San Diego, California 92152, USA
| | - Jason Mulsow
- National Marine Mammal Foundation, 2240 Shelter Island Drive #200, San Diego, California 92106, USA
| |
Collapse
|
3
|
Smith AB, Pacini AF, Nachtigall PE. Modulation rate transfer functions from four species of stranded odontocete (Stenella longirostris, Feresa attenuata, Globicephala melas, and Mesoplodon densirostris). J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2018; 204:377-389. [PMID: 29350260 DOI: 10.1007/s00359-018-1246-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 01/02/2018] [Accepted: 01/08/2018] [Indexed: 10/18/2022]
Abstract
Odontocete marine mammals explore the environment by rapidly producing echolocation signals and receiving the corresponding echoes, which likewise return at very rapid rates. Thus, it is important that the auditory system has a high temporal resolution to effectively process and extract relevant information from click echoes. This study used auditory evoked potential methods to investigate auditory temporal resolution of individuals from four different odontocete species, including a spinner dolphin (Stenella longirostris), pygmy killer whale (Feresa attenuata), long-finned pilot whale (Globicephala melas), and Blainville's beaked whale (Mesoplodon densirostris). Each individual had previously stranded and was undergoing rehabilitation. Auditory Brainstem Responses (ABRs) were elicited via acoustic stimuli consisting of a train of broadband tone pulses presented at rates between 300 and 2000 Hz. Similar to other studied species, modulation rate transfer functions (MRTFs) of the studied individuals followed the shape of a low-pass filter, with the ability to process acoustic stimuli at presentation rates up to and exceeding 1250 Hz. Auditory integration times estimated from the bandwidths of the MRTFs ranged between 250 and 333 µs. The results support the hypothesis that high temporal resolution is conserved throughout the diverse range of odontocete species.
Collapse
Affiliation(s)
- Adam B Smith
- Department of Biology, University of Hawai'i at Mānoa, 2538 McCarthy Mall, Edmondson Hall Room 216, Honolulu, HI, 96822, USA. .,Hawai'i Institute of Marine Biology, 46-007 Lilipuna Road, Kāne'ohe, HI, 96744, USA.
| | - Aude F Pacini
- Department of Biology, University of Hawai'i at Mānoa, 2538 McCarthy Mall, Edmondson Hall Room 216, Honolulu, HI, 96822, USA.,Hawai'i Institute of Marine Biology, 46-007 Lilipuna Road, Kāne'ohe, HI, 96744, USA
| | - Paul E Nachtigall
- Department of Biology, University of Hawai'i at Mānoa, 2538 McCarthy Mall, Edmondson Hall Room 216, Honolulu, HI, 96822, USA.,Hawai'i Institute of Marine Biology, 46-007 Lilipuna Road, Kāne'ohe, HI, 96744, USA
| |
Collapse
|
4
|
Teeling EC, Jones G, Rossiter SJ. Phylogeny, Genes, and Hearing: Implications for the Evolution of Echolocation in Bats. BAT BIOACOUSTICS 2016. [DOI: 10.1007/978-1-4939-3527-7_2] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
|
5
|
Seasonal plasticity in auditory processing of the envelope and temporal fine structure of sounds in three songbirds. Anim Behav 2015. [DOI: 10.1016/j.anbehav.2015.01.036] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
|
6
|
Supin AY, Popov VV. Evoked-potential recovery during double click stimulation in a beluga whale: implications for biosonar gain control. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2015; 137:2512-2521. [PMID: 25994684 DOI: 10.1121/1.4919300] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Auditory evoked potentials (AEPs) were recorded in a beluga whale Delphinapterus leucas using a double-pulse stimulation paradigm, specifically measuring the recovery (release from masking) of the second (test) response as a function of delay after the first (conditioning) pulse at various levels of the conditioning and test stimuli. The conditioning/test stimulus level ratio influenced the recovery time (the higher the ratio, the longer the recovery). This interrelation was used to evaluate the intensity/time trade in release from forward masking. Trade was evaluated as 32.2 dB per time decade. Data were considered as simulating interactions between the transmitted pulse and echo during echolocation, assuming that a transmitted sonar pulse produces forward masking of the echo response. With increased target distance, the attenuation of the echo may be compensated by the release from masking. According to the model, the compensation results in substantial stabilization of the echo response even if the intensity/time trade of release from masking is not precisely equal to the rate of echo attenuation with distance.
Collapse
Affiliation(s)
- Alexander Ya Supin
- Institute of Ecology and Evolution, Russian Academy of Sciences., 33 Leninsky Prospect, 119071 Moscow, Russia
| | - Vladimir V Popov
- Institute of Ecology and Evolution, Russian Academy of Sciences., 33 Leninsky Prospect, 119071 Moscow, Russia
| |
Collapse
|
7
|
Schrode KM, Bee MA. Evolutionary adaptations for the temporal processing of natural sounds by the anuran peripheral auditory system. ACTA ACUST UNITED AC 2015; 218:837-48. [PMID: 25617467 DOI: 10.1242/jeb.115014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Sensory systems function most efficiently when processing natural stimuli, such as vocalizations, and it is thought that this reflects evolutionary adaptation. Among the best-described examples of evolutionary adaptation in the auditory system are the frequent matches between spectral tuning in both the peripheral and central auditory systems of anurans (frogs and toads) and the frequency spectra of conspecific calls. Tuning to the temporal properties of conspecific calls is less well established, and in anurans has so far been documented only in the central auditory system. Using auditory-evoked potentials, we asked whether there are species-specific or sex-specific adaptations of the auditory systems of gray treefrogs (Hyla chrysoscelis) and green treefrogs (H. cinerea) to the temporal modulations present in conspecific calls. Modulation rate transfer functions (MRTFs) constructed from auditory steady-state responses revealed that each species was more sensitive than the other to the modulation rates typical of conspecific advertisement calls. In addition, auditory brainstem responses (ABRs) to paired clicks indicated relatively better temporal resolution in green treefrogs, which could represent an adaptation to the faster modulation rates present in the calls of this species. MRTFs and recovery of ABRs to paired clicks were generally similar between the sexes, and we found no evidence that males were more sensitive than females to the temporal modulation patterns characteristic of the aggressive calls used in male-male competition. Together, our results suggest that efficient processing of the temporal properties of behaviorally relevant sounds begins at potentially very early stages of the anuran auditory system that include the periphery.
Collapse
Affiliation(s)
- Katrina M Schrode
- Graduate Program in Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA
| | - Mark A Bee
- Graduate Program in Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA Department of Ecology, Evolution and Behavior, University of Minnesota, St Paul, MN 55108, USA
| |
Collapse
|
8
|
The modulation rate transfer function of a harbour porpoise (Phocoena phocoena). J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2012; 199:115-26. [DOI: 10.1007/s00359-012-0772-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Revised: 09/21/2012] [Accepted: 10/17/2012] [Indexed: 10/27/2022]
|
9
|
Parthasarathy A, Bartlett E. Two-channel recording of auditory-evoked potentials to detect age-related deficits in temporal processing. Hear Res 2012; 289:52-62. [PMID: 22560961 PMCID: PMC3371184 DOI: 10.1016/j.heares.2012.04.014] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Revised: 04/10/2012] [Accepted: 04/17/2012] [Indexed: 10/28/2022]
Abstract
Auditory brainstem responses (ABRs), and envelope and frequency following responses (EFRs and FFRs) are widely used to study aberrant auditory processing in conditions such as aging. We have previously reported age-related deficits in auditory processing for rapid amplitude modulation (AM) frequencies using EFRs recorded from a single channel. However, sensitive testing of EFRs along a wide range of modulation frequencies is required to gain a more complete understanding of the auditory processing deficits. In this study, ABRs and EFRs were recorded simultaneously from two electrode configurations in young and old Fischer-344 rats, a common auditory aging model. Analysis shows that the two channels respond most sensitively to complementary AM frequencies. Channel 1, recorded from Fz to mastoid, responds better to faster AM frequencies in the 100-700 Hz range of frequencies, while Channel 2, recorded from the inter-aural line to the mastoid, responds better to slower AM frequencies in the 16-100 Hz range. Simultaneous recording of Channels 1 and 2 using AM stimuli with varying sound levels and modulation depths show that age-related deficits in temporal processing are not present at slower AM frequencies but only at more rapid ones, which would not have been apparent recording from either channel alone. Comparison of EFRs between un-anesthetized and isoflurane-anesthetized recordings in young animals, as well as comparison with previously published ABR waveforms, suggests that the generators of Channel 1 may emphasize more caudal brainstem structures while those of Channel 2 may emphasize more rostral auditory nuclei including the inferior colliculus and the forebrain, with the boundary of separation potentially along the cochlear nucleus/superior olivary complex. Simultaneous two-channel recording of EFRs help to give a more complete understanding of the properties of auditory temporal processing over a wide range of modulation frequencies which is useful in understanding neural representations of sound stimuli in normal, developmental or pathological conditions.
Collapse
Affiliation(s)
| | - Edward Bartlett
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
| |
Collapse
|
10
|
Mooney TA, Li S, Ketten DR, Wang K, Wang D. Auditory temporal resolution and evoked responses to pulsed sounds for the Yangtze finless porpoises (Neophocaena phocaenoides asiaeorientalis). J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2011; 197:1149-58. [DOI: 10.1007/s00359-011-0677-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2011] [Revised: 08/22/2011] [Accepted: 08/24/2011] [Indexed: 11/30/2022]
|
11
|
Finneran JJ, Mulsow J, Schlundt CE, Houser DS. Dolphin and sea lion auditory evoked potentials in response to single and multiple swept amplitude tones. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2011; 130:1038-1048. [PMID: 21877816 DOI: 10.1121/1.3608117] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Measurement of the auditory steady-state response (ASSR) is increasingly used to assess marine mammal hearing. These tests normally entail measuring the ASSR to a sequence of sinusoidally amplitude modulated tones, so that the ASSR amplitude function can be defined and the auditory threshold estimated. In this study, an alternative method was employed, where the ASSR was elicited by an amplitude modulated stimulus whose sound pressure level was slowly varied, or "swept," over a range of levels believed to bracket the threshold. The ASSR amplitude function was obtained by analyzing the resulting grand average evoked potential using a short-time Fourier transform. The suitability of this technique for hearing assessment of bottlenose dolphins and California sea lions was evaluated by comparing ASSR amplitude functions and thresholds obtained with swept amplitude and discrete, constant amplitude stimuli. When factors such as the number of simultaneous tones, the number of averages, and the frequency analysis window length were taken into account, the performance and time required for the swept-amplitude and discrete stimulus techniques were similar. The decision to use one technique over another depends on the relative importance of obtaining suprathreshold information versus the lowest possible thresholds.
Collapse
Affiliation(s)
- James J Finneran
- U.S. Navy Marine Mammal Program, Space and Naval Warfare Systems Center, San Diego, CA 92152, USA.
| | | | | | | |
Collapse
|
12
|
Schlundt CE, Dear RL, Houser DS, Bowles AE, Reidarson T, Finneran JJ. Auditory evoked potentials in two short-finned pilot whales (Globicephala macrorhynchus). THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2011; 129:1111-1116. [PMID: 21361467 DOI: 10.1121/1.3531875] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The hearing sensitivities of two short-finned pilot whales (Globicephala macrorhynchus) were investigated by measuring auditory evoked potentials generated in response to clicks and sinusoidal amplitude modulated (SAM) tones. The first whale tested, an adult female, was a long-time resident at SeaWorld San Diego with a known health history. Click-evoked responses in this animal were similar to those measured in other echolocating odontocetes. Auditory thresholds were comparable to dolphins of similar age determined with similar evoked potential methods. The region of best sensitivity was near 40 kHz and the upper limit of functional hearing was between 80 and 100 kHz. The second whale tested, a juvenile male, was recently stranded and deemed non-releasable. Click-evoked potentials were not detected in this animal and testing with SAM tones suggested severe hearing loss above 10 kHz.
Collapse
Affiliation(s)
- Carolyn E Schlundt
- ITT Corporation, 3276 Rosecrans Street, San Diego, California 92110, USA.
| | | | | | | | | | | |
Collapse
|
13
|
Parthasarathy A, Cunningham PA, Bartlett EL. Age-related differences in auditory processing as assessed by amplitude-modulation following responses in quiet and in noise. Front Aging Neurosci 2010; 2:152. [PMID: 21188162 PMCID: PMC3006655 DOI: 10.3389/fnagi.2010.00152] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2010] [Accepted: 12/01/2010] [Indexed: 11/15/2022] Open
Abstract
Our knowledge of age-related changes in auditory processing in the central auditory system is limited, unlike the changes in the peripheral hearing organs which are more extensively studied. This study aims to further understanding of temporal processing in aging using non-invasive electrophysiological measurements in a rat model system. Amplitude modulation following responses (AMFRs) were assessed using sinusoidally amplitude modulated (SAM) tones presented to aged (92- to 95-weeks old) and young (9- to 12-weeks old) Fischer-344 rats. The modulation frequency and sound level were systematically varied, and the SAM stimuli were also presented simultaneously with wideband background noise at various levels. The overall shapes and cutoff frequencies of the AMFR temporal modulation transfer functions (tMTFs) were similar between young and aged animals. The fast Fourier transform (FFT) amplitudes of the aged animals were similar to the young in the 181-512 Hz modulation frequency range, but were significantly lower at most modulation frequencies above and below. There were no significant age-related differences in the nature of growth or FFT amplitudes with change in sound level at 256 and 1024 Hz modulation frequencies. The AMFR amplitudes were also not correlated with the ABR wave I or wave III amplitudes elicited for broadband click stimuli presented at the same sound level suggesting that sustained AMFR provide complementary information to phasic ABR responses. The FFT amplitudes varied significantly between young and aged animals for SAM stimuli in the presence of background noise, depending on the modulation frequency used and signal to noise ratio. The results show that the representation of temporally modulated stimuli is similar between young and aged animals in quiet listening conditions, but diverges substantially with the addition of background noise. This is consistent with a decrease in inhibition causing altered temporal processing with age.
Collapse
Affiliation(s)
| | - Paul A. Cunningham
- Weldon School of Biomedical Engineering, Purdue UniversityWest Lafayette, IN, USA
| | - Edward L. Bartlett
- Department of Biological Sciences, Purdue UniversityWest Lafayette, IN, USA
- Weldon School of Biomedical Engineering, Purdue UniversityWest Lafayette, IN, USA
| |
Collapse
|
14
|
Finneran JJ, Houser DS, Mase-Guthrie B, Ewing RY, Lingenfelser RG. Auditory evoked potentials in a stranded Gervais' beaked whale (Mesoplodon europaeus). THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2009; 126:484-490. [PMID: 19603906 DOI: 10.1121/1.3133241] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Efforts to identify the specific causal mechanisms responsible for beaked whale strandings coincident with naval exercises have been hampered by lack of data concerning the hearing abilities of beaked whales and their physiological and behavioral responses to sound. In this study, auditory capabilities of a stranded Gervais' beaked whale (Mesoplodon europaeus) were investigated by measuring auditory evoked potentials. Click-evoked potentials, auditory thresholds as a function of frequency, and the modulation rate transfer function were determined. The evoked potentials and modulation rate transfer function were similar to those measured in other echolocating odontocetes; the upper limit of functional hearing was 80-90 kHz.
Collapse
Affiliation(s)
- James J Finneran
- US Navy Marine Mammal Program, SSC Pacific, Biosciences Division, San Diego, California 92152, USA.
| | | | | | | | | |
Collapse
|
15
|
Auditory temporal resolution of a wild white-beaked dolphin (Lagenorhynchus albirostris). J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2009; 195:375-84. [PMID: 19198850 DOI: 10.1007/s00359-009-0415-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2008] [Revised: 01/05/2009] [Accepted: 01/08/2009] [Indexed: 10/21/2022]
Abstract
Adequate temporal resolution is required across taxa to properly utilize amplitude modulated acoustic signals. Among mammals, odontocete marine mammals are considered to have relatively high temporal resolution, which is a selective advantage when processing fast traveling underwater sound. However, multiple methods used to estimate auditory temporal resolution have left comparisons among odontocetes and other mammals somewhat vague. Here we present the estimated auditory temporal resolution of an adult male white-beaked dolphin, (Lagenorhynchus albirostris), using auditory evoked potentials and click stimuli. Ours is the first of such studies performed on a wild dolphin in a capture-and-release scenario. The white-beaked dolphin followed rhythmic clicks up to a rate of approximately 1,125-1,250 Hz, after which the modulation rate transfer function (MRTF) cut-off steeply. However, 10% of the maximum response was still found at 1,450 Hz indicating high temporal resolution. The MRTF was similar in shape and bandwidth to that of other odontocetes. The estimated maximal temporal resolution of white-beaked dolphins and other odontocetes was approximately twice that of pinnipeds and manatees, and more than ten-times faster than humans and gerbils. The exceptionally high temporal resolution abilities of odontocetes are likely due primarily to echolocation capabilities that require rapid processing of acoustic cues.
Collapse
|
16
|
Feng Y, Yin S, Wang J. Cortical responses to amplitude modulation in guinea pigs and the effects of general anesthesia by pentobarbital. Hear Res 2009; 247:40-6. [DOI: 10.1016/j.heares.2008.10.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2008] [Revised: 10/15/2008] [Accepted: 10/16/2008] [Indexed: 10/21/2022]
|
17
|
Branstetter BK, Finneran JJ, Houser DS. Frequency and level dependent masking of the multiple auditory steady-state response in the bottlenose dolphin (Tursiops truncatus). THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2008; 123:2928-2935. [PMID: 18529209 DOI: 10.1121/1.2896753] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The potential for interactions between steady-state evoked responses to simultaneous auditory stimuli was investigated in two bottlenose dolphins (Tursiops truncatus). Three experiments were conducted using either a probe stimulus (probe condition) or a probe in the presence of a masker (probe-plus-masker condition). In the first experiment, the probe and masker were sinusoidal amplitude-modulated (SAM) tones. Probe and masker frequencies and masker level were manipulated to provide variable masking conditions. Probe frequencies were 31.7, 63.5, 100.8, and 127.0 kHz. The second experiment was identical to the first except only the 63.5 kHz probe was used and maskers were pure tones. For the third experiment, thresholds were measured for the probe and probe-plus-masker conditions using two techniques, one based on the lowest detectable response and the other based on a regression analysis. Results demonstrated localized masking effects where lower frequency maskers suppressed higher frequency probes and higher amplitude maskers produced a greater masking effect. The pattern of pure tone masking was nearly identical to SAM tone masking. The two threshold estimates were similar in low masking conditions, but in high masking conditions the lowest detectable response tended to overestimate thresholds while the regression-based analysis tended to underestimate thresholds.
Collapse
Affiliation(s)
- Brian K Branstetter
- US Navy Marine Mammal Program, Space and Naval Warfare Systems Center, San Diego, Code 71510, 53560 Hull Street, San Diego, California 92152, USA.
| | | | | |
Collapse
|
18
|
Finneran JJ, Houser DS, Blasko D, Hicks C, Hudson J, Osborn M. Estimating bottlenose dolphin (Tursiops truncatus) hearing thresholds from single and multiple simultaneous auditory evoked potentials. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2008; 123:542-551. [PMID: 18177181 DOI: 10.1121/1.2812595] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Hearing thresholds were estimated in four bottlenose dolphins by measuring auditory evoked responses to single and multiple sinusoidal amplitude modulated tones. Subjects consisted of two males and two females with ages from 4 to 22 years. Testing was conducted in air using a "jawphone" transducer to couple sound into each subject's lower right jaw. Carrier frequencies ranged from 10 to 160 kHz in one-half octave steps. Amplitude modulated stimuli were presented individually and as the sum of four, five, and nine simultaneous tones with unique carrier and modulation frequencies. Evoked potentials were noninvasively recorded using surface electrodes embedded in silicon suction cups. The presence or absence of an evoked response at each modulation frequency was assessed by calculating the magnitude-squared coherence from the frequency spectra of the recorded sweeps. All subjects exhibited traditional "U-shaped" audiograms with upper cutoff frequencies above 113 kHz. The time required for threshold estimates ranged from 23 to 37 min for single stimuli to 5-9 min for nine simultaneous stimuli. Agreement between thresholds estimated from single stimuli and multiple, simultaneous stimuli was generally good, indicating that multiple stimuli may be used for quick hearing assessment when time is limited.
Collapse
Affiliation(s)
- James J Finneran
- U.S. Navy Marine Mammal Program, Space and Naval Warfare Systems Center, San Diego, Code 71510, 53560 Hull Street, San Diego, California 92152, USA.
| | | | | | | | | | | |
Collapse
|