Richard Fay - Academia.edu (original) (raw)
Papers by Richard Fay
The Journal of Experimental Biology, May 15, 2009
Comparisons of left and right auditory input are required for sound source localization in most t... more Comparisons of left and right auditory input are required for sound source localization in most terrestrial vertebrates. Previous physiological and neuroanatomical studies have indicated that binaural convergence is present in the ascending auditory system of the toadfish. In this study, we introduce a new technique, otolith tipping, to reversibly alter directional auditory input to the central nervous system of a fish. The normal directional response pattern (DRP) was recorded extracellularly for auditory cells in the first-order descending octaval nucleus (DON) or the midbrain torus semicircularis (TS) using particle motion stimuli in the horizontal and mid-sagittal planes. The same stimuli were used during tipping of the saccular otolith to evaluate changes in the DRPs. Post-tipping DRPs were generated and compared with the pre-tipping DRPs to ensure that the data had been collected consistently from the same unit. In the DON, ipsilateral or contralateral tipping most often eliminated spike activity, but changes in spike rate (±) and DRP shape were also documented. In the TS, tipping most often caused a change in spike rate (±) and altered the shape or best axis of the DRP. The data indicate that there are complex interactions of excitatory and inhibitory inputs in the DON and TS resulting from the convergence of binaural inputs. As in anurans, but unlike other terrestrial vertebrates, binaural processing associated with encoding the direction of a sound source begins in the first-order auditory nucleus of this teleost.
American zoologist, May 1, 1977
SYNOPSIS Behavioral evidence indicates that sharks detect underwater sound at frequencies up to 1... more SYNOPSIS Behavioral evidence indicates that sharks detect underwater sound at frequencies up to 1000 Hz, and that certain low frequency signals attract sharks from large distances. It appears that the adequate stimulus for "sound detecting" systems of the shark is panicle motion, as opposed to fluctuations in sound pressure. The elasmobranch ear consists of the three semi-circular canals for detecting angular accelerations, and otolith organs for detecting linear motion and accelerations due to gravity. Two of these organs, the sacculus and macula neglecta, have been shown to be responsive to vibratory motion, with the macula neglecta having best sensitivity to vertical movements. A direct vibrational pathway exists to the macula neglecta from the parietal fossa of the dorsal chondrocranium. It is not clear at present, however, whether it is the inner ear or the lateral line system which is responsible for hearing. Both detection systems are theoretically capable of providing information to the brain about sound source location using non-parallel arrays of directionally sensitive hair-cell receptors. Recent theories of underwater sound localization by fishes and sharks suggest that the ability to detect a vertical displacement component of an acoustic signal (e. g., via the macula neglecta) is necessary for instantaneous location decisions. It is not known, however, whether the sharks localize by processing information about various aspects of the sound field simultaneously (in parallel), or whether the sound field is sampled successively at different points in space. Clearly, more experimental work on the physiology of elasmobranch acoustic behavior is called for.
Auditory Evoked Potential Audiograms Compared with Behavioral Audiograms in Aquatic Animals
Advances in Experimental Medicine and Biology, 2016
Auditory evoked potentials (AEPs) have become popular for estimating hearing thresholds and audio... more Auditory evoked potentials (AEPs) have become popular for estimating hearing thresholds and audiograms. What is the utility of these measurements? How do AEP audiograms compare with behavioral audiograms? In general, AEP measurements for fishes and marine mammals often underestimate behavioral thresholds, but comparisons are especially complicated when the AEP and behavioral measures are obtained under different acoustic conditions. There is no single representative relationship between AEP and behavioral audiograms and these audiograms should not be considered equivalent. We suggest that the most valuable comparisons are those made by the same researcher using similar acoustic conditions for both measurements.
Journal of the Acoustical Society of America, Apr 1, 2009
This work is an investigation of coding strategies for spectral analysis and sound source locatio... more This work is an investigation of coding strategies for spectral analysis and sound source location in Acipenser fulvescens, the lake sturgeon. A. fulvescens belongs to one of the few extant non-teleost ray-finned fishes. The sturgeon taxonomic family, the (Acipenseridae), has a phylogenetic history that dates back about 200 million years. Studies on sensory coding in any species of this family or
Journal of the Acoustical Society of America, Feb 1, 2023
Machine-learning-based simultaneous detection and ranging of impulsive baleen whale vocalizations... more Machine-learning-based simultaneous detection and ranging of impulsive baleen whale vocalizations using a single hydrophone
Brain Behavior and Evolution, 1993
The literature on fish hearing has increased significantly since our last critical review in 1973... more The literature on fish hearing has increased significantly since our last critical review in 1973. The purpose of the current paper is to review the more recent lit erature and to identify those questions that need to he asked to develop a fuller understanding of the auditory capabilities and processing mechanisms of fishes. Wc conclude that while our understanding of fish hearing has increased substan tially in the past years, there are still major gaps in what wc know. In particular, the comparative functional literature is extremely limited, and wc do not yet know whether different species, and particularly hearing specialists as compared to hearing nonspecialists, have fundamentally different auditory capabilities and mechanisms.
Journal of the Acoustical Society of America, Mar 1, 2019
Forum is intended for communications that raise acoustical concerns, express acoustical viewpoint... more Forum is intended for communications that raise acoustical concerns, express acoustical viewpoints, or stimulate acoustical research and applications without necessarily including new findings. Publication will occur on a selective basis when such communications have particular relevance, importance, or interest to the acoustical community or the Society.
Springer handbook of auditory research, 2016
the material is concerned, specifi cally the rights of translation, reprinting, reuse of illustra... more the material is concerned, specifi cally the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfi lms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specifi c statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use.
The Journal of Experimental Biology, May 1, 2010
Acipenser fulvescens, the lake sturgeon, belongs to one of the few extant non-teleost ray-finned ... more Acipenser fulvescens, the lake sturgeon, belongs to one of the few extant non-teleost ray-finned (bony) fishes. The sturgeons (family Acipenseridae) have a phylogenetic history that dates back about 250 million years. The study reported here is the first investigation of peripheral coding strategies for spectral analysis in the auditory system in a non-teleost bony fish. We used a shaker system to simulate the particle motion component of sound during electrophysiological recordings of isolated single units from the eighth nerve innervating the saccule and lagena. Background activity and response characteristics of saccular and lagenar afferents (such as thresholds, response-level functions and temporal firing) resembled the ones found in teleosts. The distribution of best frequencies also resembled data in teleosts (except for Carassius auratus, goldfish) tested with the same stimulation method. The saccule and lagena in A. fulvescens contain otoconia, in contrast to the solid otoliths found in teleosts, however, this difference in otolith structure did not appear to affect threshold, frequency tuning, intensity-or temporal responses of auditory afferents. In general, the physiological characteristics common to A. fulvescens, teleosts and land vertebrates reflect important functions of the auditory system that may have been conserved throughout the evolution of vertebrates.
Brain Behavior and Evolution, 2012
RESEARCH ARTICLE Local acoustic particle motion guides sound-source localization behavior in the plainfin midshipman fish, Porichthys notatus
Sound Source Localization
The Journal of the Acoustical Society of America, 1983
Three-dimensional maps of directional sensitivity were constructed for single fibers of the saccu... more Three-dimensional maps of directional sensitivity were constructed for single fibers of the saccular, lagenar, and utricular nerves by measuring acceleration thresholds to sinusoidal motion oriented along 40 axes in three orthogonal planes. Stimuli were generated by adding three mutually perpendicular vibration inputs to a rigid cylinder containing water (and the fish). The phases and amplitudes of the inputs were computed to achieve linear motion vectors with particular orientations, as determined by an accelerometer array. Phase-locking was used to define a cell's acceleration sensitivity, and the polarity of the response (the excitatory direction of motion). In general, the 3-D directional sensitivity of cells (in dB) is described by a solid composed of two tangent spheroids, with an axis of greatest sensitivity passing through their centers. In the saccule, these axes are oriented primarily dorsal-ventrally with deviations from vertical of up to 40°. Lagenar fibers show simi...
The Journal of Experimental Biology, 2014
We investigated the roles of the swim bladder and the lateral line system in sound localization b... more We investigated the roles of the swim bladder and the lateral line system in sound localization behavior by the plainfin midshipman fish (Porichthys notatus). Reproductive female midshipman underwent either surgical deflation of the swim bladder or cryoablation of the lateral line and were then tested in a monopolar sound source localization task. Fish with nominally 'deflated' swim bladders performed similar to sham-deflated controls; however, postexperiment evaluation of swim bladder deflation revealed that a majority of 'deflated' fish (88%, seven of the eight fish) that exhibited positive phonotaxis had partially inflated swim bladders. In total, 95% (21/22) of fish that localized the source had at least partially inflated swim bladders, indicating that pressure reception is likely required for sound source localization. In lateral line experiments, no difference was observed in the proportion of females exhibiting positive phonotaxis with ablated (37%) versus sham-ablated (47%) lateral line systems. These data suggest that the lateral line system is likely not required for sound source localization, although this system may be important for fine-tuning the approach to the sound source. We found that midshipman can solve the 180 deg ambiguity of source direction in the shallow water of our test tank, which is similar to their nesting environment. We also found that the potential directional cues (phase relationship between pressure and particle motion) in shallow water differs from a theoretical free-field. Therefore, the general question of how fish use acoustic pressure cues to solve the 180 deg ambiguity of source direction from the particle motion vector remains unresolved.
Auditory saccular potentials of the little skate, Raja erinacea
Journal of the Acoustical Society of America, Apr 1, 2009
Previous behavioral studies have shown that elasmobranch fishes can be attracted to low-frequency... more Previous behavioral studies have shown that elasmobranch fishes can be attracted to low-frequency sound sources (< 80 Hz) in their natural habitat, but relatively few studies have characterized the auditory response properties of the elasmobranch inner ear to low-frequency sounds. Here, we examine the response properties of evoked saccular potentials from the skate inner ear to determine the auditory threshold sensitivity and frequency response of saccular hair cells to low-frequency stimuli. Saccular potentials were recorded from the medial region of the saccule while sound was generated using a shaker table designed to mimic the particle motion component of sound. Four test frequencies (50, 64, 84, and 100 Hz) and 11 directions were used to characterize the displacement sensitivity, frequency response, and directional response properties of the skate saccule. Saccular potentials were evoked and measured at twice the stimulus frequency in vivo using a wave analyzer, while stimuli were generated via the shaker table system. The right and left saccule appeared to have an omnidirectional response based on our initial measurements, but the frequency response of the skate saccule had lower displacement thresholds at 84 and 100 Hz compared to stimuli at 50 and 64 Hz.
Directional and frequency saccular sensitivity of the little skate, Raja erinacea
Journal of the Acoustical Society of America, Apr 1, 2011
Although a number of previous behavioral studies have demonstrated that elasmobranch fishes can d... more Although a number of previous behavioral studies have demonstrated that elasmobranch fishes can detect and are attracted to low frequency sounds, few physiological studies have characterized the auditory response properties of the elasmobranch inner ear to such low frequency sounds. In this study, we examined the directional and frequency responses of the inner ear saccule in the little skate, Raja erinacea to low frequency stimuli. Evoked microphonic potentials were recorded from the middle region of the saccule while sound was generated using a shaker table designed to mimic the particle motion vector component of sound. 8 test frequencies (50, 64, 84, 100, 140, 185, 243, and 303 Hz) and 11 directions were used to characterize the displacement sensitivity, frequency response and directional response properties of the skate saccule. Saccular potentials were evoked and measured at twice the stimulus frequency in vivo using a wave analyzer while stimuli were generated via the shaker table system. The right and left saccules appeared to have an omnidirectional response based on initial measurements, and the frequency response of the skate saccule had lowest displacement thresholds from 100 to 185 Hz.
HEARING AND LATERAL LINE | Sound Source Localization and Directional Hearing in Fishes
Elsevier eBooks, 2011
The behavioral capacity for directional hearing and the discrimination of sound sources at differ... more The behavioral capacity for directional hearing and the discrimination of sound sources at different locations has been demonstrated in a number of fish species. Evidence suggests that all fishes can detect the acoustic particle motion component of sound using their ears. Few experiments, however, provide conclusive evidence that fishes can find the location of sound sources, and debate remains about whether fishes know where sound sources are in the same way as human listeners or if they have other strategies for finding sound sources. It is still uncertain how sound source localization by fishes is accomplished.
Sound source localization of a dipole by the plainfin midshipman fish (Porichthys notatus)
Journal of the Acoustical Society of America, Mar 1, 2010
Localization of a dipole sound source was studied in female plainfin midshipman fish (Porichthys ... more Localization of a dipole sound source was studied in female plainfin midshipman fish (Porichthys notatus). Experiments were conducted and videotaped in a 3.65-m-diameter tank using a dipole underwater speaker system placed near the center of the tank. The sound was a 90-Hz tone, approximately the fundamental frequency of the male’s advertisement call. Pressure and particle motion components of the sound field were mapped with 9-cm resolution. Pressure was measured using an eight-hydrophone array, and particle motion vectors calculated from the pressure gradients. Mapping confirmed that the projector was operating as a dipole. Gravid fish were released 70 cm from the sound source at two different positions relative to the dipole axis: one near the dipole axis and one near the pressure null axis. Twenty-five positive responses were recorded from each release site. The phonotactic response pathways along the dipole axis consisted of slightly curved tracks to the sound source, whereas pathways from the null axis consisted of greatly curved tracks to the source that followed the particle motion vectors. Results confirm that fish can locate a dipole sound source and are sensitive to the direction of acoustic particle motion. [Work supported by NSF.]
The Journal of Experimental Biology, 2012
Sound-source localization behavior was studied in the plainfin midshipman fish (Porichthys notatu... more Sound-source localization behavior was studied in the plainfin midshipman fish (Porichthys notatus) by making use of the naturally occurring phonotaxis response of gravid females to playback of the maleʼs advertisement call. The observations took place outdoors in a circular concrete tank. A dipole sound projector was placed at the center of the tank and an 80-90Hz tone (the approximate fundamental frequency to the maleʼs advertisement call) was broadcast to gravid females that were released from alternative sites approximately 100cm from the source. The phonotaxic responses of females to the source were recorded, analyzed and compared with the sound field. One release site was approximately along the vibratory axis of the dipole source, and the other was approximately orthogonal to the vibratory axis. The sound field in the tank was fully characterized through measurements of the sound pressure field using hydrophones and acoustic particle motion using an accelerometer. These measurements confirmed that the sound field was a nearly ideal dipole. When released along the dipole vibratory axis, the responding female fish took essentially straight paths to the source. However, when released approximately 90deg to the sourceʼs vibratory axis, the responding females took highly curved paths to the source that were approximately in line with the local particle motion axes. These results indicate that the acoustic cues used by fish during sound-source localization include the axes of particle motion of the local sound field.
The Journal of Experimental Biology, May 15, 2009
Comparisons of left and right auditory input are required for sound source localization in most t... more Comparisons of left and right auditory input are required for sound source localization in most terrestrial vertebrates. Previous physiological and neuroanatomical studies have indicated that binaural convergence is present in the ascending auditory system of the toadfish. In this study, we introduce a new technique, otolith tipping, to reversibly alter directional auditory input to the central nervous system of a fish. The normal directional response pattern (DRP) was recorded extracellularly for auditory cells in the first-order descending octaval nucleus (DON) or the midbrain torus semicircularis (TS) using particle motion stimuli in the horizontal and mid-sagittal planes. The same stimuli were used during tipping of the saccular otolith to evaluate changes in the DRPs. Post-tipping DRPs were generated and compared with the pre-tipping DRPs to ensure that the data had been collected consistently from the same unit. In the DON, ipsilateral or contralateral tipping most often eliminated spike activity, but changes in spike rate (±) and DRP shape were also documented. In the TS, tipping most often caused a change in spike rate (±) and altered the shape or best axis of the DRP. The data indicate that there are complex interactions of excitatory and inhibitory inputs in the DON and TS resulting from the convergence of binaural inputs. As in anurans, but unlike other terrestrial vertebrates, binaural processing associated with encoding the direction of a sound source begins in the first-order auditory nucleus of this teleost.
American zoologist, May 1, 1977
SYNOPSIS Behavioral evidence indicates that sharks detect underwater sound at frequencies up to 1... more SYNOPSIS Behavioral evidence indicates that sharks detect underwater sound at frequencies up to 1000 Hz, and that certain low frequency signals attract sharks from large distances. It appears that the adequate stimulus for "sound detecting" systems of the shark is panicle motion, as opposed to fluctuations in sound pressure. The elasmobranch ear consists of the three semi-circular canals for detecting angular accelerations, and otolith organs for detecting linear motion and accelerations due to gravity. Two of these organs, the sacculus and macula neglecta, have been shown to be responsive to vibratory motion, with the macula neglecta having best sensitivity to vertical movements. A direct vibrational pathway exists to the macula neglecta from the parietal fossa of the dorsal chondrocranium. It is not clear at present, however, whether it is the inner ear or the lateral line system which is responsible for hearing. Both detection systems are theoretically capable of providing information to the brain about sound source location using non-parallel arrays of directionally sensitive hair-cell receptors. Recent theories of underwater sound localization by fishes and sharks suggest that the ability to detect a vertical displacement component of an acoustic signal (e. g., via the macula neglecta) is necessary for instantaneous location decisions. It is not known, however, whether the sharks localize by processing information about various aspects of the sound field simultaneously (in parallel), or whether the sound field is sampled successively at different points in space. Clearly, more experimental work on the physiology of elasmobranch acoustic behavior is called for.
Auditory Evoked Potential Audiograms Compared with Behavioral Audiograms in Aquatic Animals
Advances in Experimental Medicine and Biology, 2016
Auditory evoked potentials (AEPs) have become popular for estimating hearing thresholds and audio... more Auditory evoked potentials (AEPs) have become popular for estimating hearing thresholds and audiograms. What is the utility of these measurements? How do AEP audiograms compare with behavioral audiograms? In general, AEP measurements for fishes and marine mammals often underestimate behavioral thresholds, but comparisons are especially complicated when the AEP and behavioral measures are obtained under different acoustic conditions. There is no single representative relationship between AEP and behavioral audiograms and these audiograms should not be considered equivalent. We suggest that the most valuable comparisons are those made by the same researcher using similar acoustic conditions for both measurements.
Journal of the Acoustical Society of America, Apr 1, 2009
This work is an investigation of coding strategies for spectral analysis and sound source locatio... more This work is an investigation of coding strategies for spectral analysis and sound source location in Acipenser fulvescens, the lake sturgeon. A. fulvescens belongs to one of the few extant non-teleost ray-finned fishes. The sturgeon taxonomic family, the (Acipenseridae), has a phylogenetic history that dates back about 200 million years. Studies on sensory coding in any species of this family or
Journal of the Acoustical Society of America, Feb 1, 2023
Machine-learning-based simultaneous detection and ranging of impulsive baleen whale vocalizations... more Machine-learning-based simultaneous detection and ranging of impulsive baleen whale vocalizations using a single hydrophone
Brain Behavior and Evolution, 1993
The literature on fish hearing has increased significantly since our last critical review in 1973... more The literature on fish hearing has increased significantly since our last critical review in 1973. The purpose of the current paper is to review the more recent lit erature and to identify those questions that need to he asked to develop a fuller understanding of the auditory capabilities and processing mechanisms of fishes. Wc conclude that while our understanding of fish hearing has increased substan tially in the past years, there are still major gaps in what wc know. In particular, the comparative functional literature is extremely limited, and wc do not yet know whether different species, and particularly hearing specialists as compared to hearing nonspecialists, have fundamentally different auditory capabilities and mechanisms.
Journal of the Acoustical Society of America, Mar 1, 2019
Forum is intended for communications that raise acoustical concerns, express acoustical viewpoint... more Forum is intended for communications that raise acoustical concerns, express acoustical viewpoints, or stimulate acoustical research and applications without necessarily including new findings. Publication will occur on a selective basis when such communications have particular relevance, importance, or interest to the acoustical community or the Society.
Springer handbook of auditory research, 2016
the material is concerned, specifi cally the rights of translation, reprinting, reuse of illustra... more the material is concerned, specifi cally the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfi lms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specifi c statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use.
The Journal of Experimental Biology, May 1, 2010
Acipenser fulvescens, the lake sturgeon, belongs to one of the few extant non-teleost ray-finned ... more Acipenser fulvescens, the lake sturgeon, belongs to one of the few extant non-teleost ray-finned (bony) fishes. The sturgeons (family Acipenseridae) have a phylogenetic history that dates back about 250 million years. The study reported here is the first investigation of peripheral coding strategies for spectral analysis in the auditory system in a non-teleost bony fish. We used a shaker system to simulate the particle motion component of sound during electrophysiological recordings of isolated single units from the eighth nerve innervating the saccule and lagena. Background activity and response characteristics of saccular and lagenar afferents (such as thresholds, response-level functions and temporal firing) resembled the ones found in teleosts. The distribution of best frequencies also resembled data in teleosts (except for Carassius auratus, goldfish) tested with the same stimulation method. The saccule and lagena in A. fulvescens contain otoconia, in contrast to the solid otoliths found in teleosts, however, this difference in otolith structure did not appear to affect threshold, frequency tuning, intensity-or temporal responses of auditory afferents. In general, the physiological characteristics common to A. fulvescens, teleosts and land vertebrates reflect important functions of the auditory system that may have been conserved throughout the evolution of vertebrates.
Brain Behavior and Evolution, 2012
RESEARCH ARTICLE Local acoustic particle motion guides sound-source localization behavior in the plainfin midshipman fish, Porichthys notatus
Sound Source Localization
The Journal of the Acoustical Society of America, 1983
Three-dimensional maps of directional sensitivity were constructed for single fibers of the saccu... more Three-dimensional maps of directional sensitivity were constructed for single fibers of the saccular, lagenar, and utricular nerves by measuring acceleration thresholds to sinusoidal motion oriented along 40 axes in three orthogonal planes. Stimuli were generated by adding three mutually perpendicular vibration inputs to a rigid cylinder containing water (and the fish). The phases and amplitudes of the inputs were computed to achieve linear motion vectors with particular orientations, as determined by an accelerometer array. Phase-locking was used to define a cell's acceleration sensitivity, and the polarity of the response (the excitatory direction of motion). In general, the 3-D directional sensitivity of cells (in dB) is described by a solid composed of two tangent spheroids, with an axis of greatest sensitivity passing through their centers. In the saccule, these axes are oriented primarily dorsal-ventrally with deviations from vertical of up to 40°. Lagenar fibers show simi...
The Journal of Experimental Biology, 2014
We investigated the roles of the swim bladder and the lateral line system in sound localization b... more We investigated the roles of the swim bladder and the lateral line system in sound localization behavior by the plainfin midshipman fish (Porichthys notatus). Reproductive female midshipman underwent either surgical deflation of the swim bladder or cryoablation of the lateral line and were then tested in a monopolar sound source localization task. Fish with nominally 'deflated' swim bladders performed similar to sham-deflated controls; however, postexperiment evaluation of swim bladder deflation revealed that a majority of 'deflated' fish (88%, seven of the eight fish) that exhibited positive phonotaxis had partially inflated swim bladders. In total, 95% (21/22) of fish that localized the source had at least partially inflated swim bladders, indicating that pressure reception is likely required for sound source localization. In lateral line experiments, no difference was observed in the proportion of females exhibiting positive phonotaxis with ablated (37%) versus sham-ablated (47%) lateral line systems. These data suggest that the lateral line system is likely not required for sound source localization, although this system may be important for fine-tuning the approach to the sound source. We found that midshipman can solve the 180 deg ambiguity of source direction in the shallow water of our test tank, which is similar to their nesting environment. We also found that the potential directional cues (phase relationship between pressure and particle motion) in shallow water differs from a theoretical free-field. Therefore, the general question of how fish use acoustic pressure cues to solve the 180 deg ambiguity of source direction from the particle motion vector remains unresolved.
Auditory saccular potentials of the little skate, Raja erinacea
Journal of the Acoustical Society of America, Apr 1, 2009
Previous behavioral studies have shown that elasmobranch fishes can be attracted to low-frequency... more Previous behavioral studies have shown that elasmobranch fishes can be attracted to low-frequency sound sources (< 80 Hz) in their natural habitat, but relatively few studies have characterized the auditory response properties of the elasmobranch inner ear to low-frequency sounds. Here, we examine the response properties of evoked saccular potentials from the skate inner ear to determine the auditory threshold sensitivity and frequency response of saccular hair cells to low-frequency stimuli. Saccular potentials were recorded from the medial region of the saccule while sound was generated using a shaker table designed to mimic the particle motion component of sound. Four test frequencies (50, 64, 84, and 100 Hz) and 11 directions were used to characterize the displacement sensitivity, frequency response, and directional response properties of the skate saccule. Saccular potentials were evoked and measured at twice the stimulus frequency in vivo using a wave analyzer, while stimuli were generated via the shaker table system. The right and left saccule appeared to have an omnidirectional response based on our initial measurements, but the frequency response of the skate saccule had lower displacement thresholds at 84 and 100 Hz compared to stimuli at 50 and 64 Hz.
Directional and frequency saccular sensitivity of the little skate, Raja erinacea
Journal of the Acoustical Society of America, Apr 1, 2011
Although a number of previous behavioral studies have demonstrated that elasmobranch fishes can d... more Although a number of previous behavioral studies have demonstrated that elasmobranch fishes can detect and are attracted to low frequency sounds, few physiological studies have characterized the auditory response properties of the elasmobranch inner ear to such low frequency sounds. In this study, we examined the directional and frequency responses of the inner ear saccule in the little skate, Raja erinacea to low frequency stimuli. Evoked microphonic potentials were recorded from the middle region of the saccule while sound was generated using a shaker table designed to mimic the particle motion vector component of sound. 8 test frequencies (50, 64, 84, 100, 140, 185, 243, and 303 Hz) and 11 directions were used to characterize the displacement sensitivity, frequency response and directional response properties of the skate saccule. Saccular potentials were evoked and measured at twice the stimulus frequency in vivo using a wave analyzer while stimuli were generated via the shaker table system. The right and left saccules appeared to have an omnidirectional response based on initial measurements, and the frequency response of the skate saccule had lowest displacement thresholds from 100 to 185 Hz.
HEARING AND LATERAL LINE | Sound Source Localization and Directional Hearing in Fishes
Elsevier eBooks, 2011
The behavioral capacity for directional hearing and the discrimination of sound sources at differ... more The behavioral capacity for directional hearing and the discrimination of sound sources at different locations has been demonstrated in a number of fish species. Evidence suggests that all fishes can detect the acoustic particle motion component of sound using their ears. Few experiments, however, provide conclusive evidence that fishes can find the location of sound sources, and debate remains about whether fishes know where sound sources are in the same way as human listeners or if they have other strategies for finding sound sources. It is still uncertain how sound source localization by fishes is accomplished.
Sound source localization of a dipole by the plainfin midshipman fish (Porichthys notatus)
Journal of the Acoustical Society of America, Mar 1, 2010
Localization of a dipole sound source was studied in female plainfin midshipman fish (Porichthys ... more Localization of a dipole sound source was studied in female plainfin midshipman fish (Porichthys notatus). Experiments were conducted and videotaped in a 3.65-m-diameter tank using a dipole underwater speaker system placed near the center of the tank. The sound was a 90-Hz tone, approximately the fundamental frequency of the male’s advertisement call. Pressure and particle motion components of the sound field were mapped with 9-cm resolution. Pressure was measured using an eight-hydrophone array, and particle motion vectors calculated from the pressure gradients. Mapping confirmed that the projector was operating as a dipole. Gravid fish were released 70 cm from the sound source at two different positions relative to the dipole axis: one near the dipole axis and one near the pressure null axis. Twenty-five positive responses were recorded from each release site. The phonotactic response pathways along the dipole axis consisted of slightly curved tracks to the sound source, whereas pathways from the null axis consisted of greatly curved tracks to the source that followed the particle motion vectors. Results confirm that fish can locate a dipole sound source and are sensitive to the direction of acoustic particle motion. [Work supported by NSF.]
The Journal of Experimental Biology, 2012
Sound-source localization behavior was studied in the plainfin midshipman fish (Porichthys notatu... more Sound-source localization behavior was studied in the plainfin midshipman fish (Porichthys notatus) by making use of the naturally occurring phonotaxis response of gravid females to playback of the maleʼs advertisement call. The observations took place outdoors in a circular concrete tank. A dipole sound projector was placed at the center of the tank and an 80-90Hz tone (the approximate fundamental frequency to the maleʼs advertisement call) was broadcast to gravid females that were released from alternative sites approximately 100cm from the source. The phonotaxic responses of females to the source were recorded, analyzed and compared with the sound field. One release site was approximately along the vibratory axis of the dipole source, and the other was approximately orthogonal to the vibratory axis. The sound field in the tank was fully characterized through measurements of the sound pressure field using hydrophones and acoustic particle motion using an accelerometer. These measurements confirmed that the sound field was a nearly ideal dipole. When released along the dipole vibratory axis, the responding female fish took essentially straight paths to the source. However, when released approximately 90deg to the sourceʼs vibratory axis, the responding females took highly curved paths to the source that were approximately in line with the local particle motion axes. These results indicate that the acoustic cues used by fish during sound-source localization include the axes of particle motion of the local sound field.