James J Finneran

Navy's Space and Naval Warfare Systems Command, San Diego, California, United States

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Publications (154)246.62 Total impact

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    ABSTRACT: Bottlenose dolphins performing echolocation tasks at long ranges may utilize a transmission mode where bursts, or "packets," of echolocation clicks are emitted rather than single clicks. The clicks within each packet are separated by time intervals well below the two-way travel time, while the packets themselves are emitted at intervals greater than the two-way travel time. Packet use has been shown to increase with range; however, the exact function of packets and the advantages gained by their utilization remain unknown. In this study, the capability for dolphins to utilize multi-echo processing within packets of echoes was investigated by manipulating the number of available echoes within each packet as a dolphin performed a long-range echolocation task. The results showed an improvement in detectability with an increase in the number of echoes in each packet and suggest that packet use is an adaptation to allow multi-echo processing at long ranges without introducing range ambiguity.
    The Journal of the Acoustical Society of America 11/2014; 136(5):2876. · 1.65 Impact Factor
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    ABSTRACT: Previous measurements of toothed whale echolocation transmission beam patterns have utilized few hydrophones and have therefore been limited to fine angular resolution only near the principal axis or poor resolution over larger azimuthal ranges. In this study, a circular, horizontal planar array of 35 hydrophones was used to measure a dolphin's transmission beam pattern with 5° to 10° resolution at azimuths from -150° to +150°. Beam patterns and directivity indices were calculated from both the peak-peak sound pressure and the energy flux density. The emitted pulse became smaller in amplitude and progressively distorted as it was recorded farther off the principal axis. Beyond ±30° to 40°, the off-axis signal consisted of two distinct pulses whose difference in time of arrival increased with the absolute value of the azimuthal angle. A simple model suggests that the second pulse is best explained as a reflection from internal structures in the dolphin's head, and does not implicate the use of a second sound source. Click energy was also more directional at the higher source levels utilized at longer ranges, where the center frequency was elevated compared to that of the lower amplitude clicks used at shorter range.
    The Journal of the Acoustical Society of America 10/2014; 136(4):2025. · 1.65 Impact Factor
  • Jason Mulsow, James J Finneran, Dorian S Houser
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    ABSTRACT: Suction cup transducers, also known as "jawphones," are now commonly used to deliver acoustic stimuli to odontocete cetaceans during hearing studies. It is often assumed that stimulation is primarily limited to the ear ipsilateral to a jawphone; however, the actual differences in auditory stimulation at the two ears are not well understood. To examine these differences, auditory evoked potentials (AEPs) were simultaneously recorded from both ears during jawphone stimulation in two bottlenose dolphins. The amplitudes and latencies of auditory nerve responses (ANRs) elicited by broadband clicks were measured as functions of stimulus level and used to estimate the difference in received level and interaural time difference (ITD) between the two ears. Results indicated that clicks received at the ear contralateral to the jawphone were attenuated by approximately 20 dB relative to the level at the ipsilateral ear. The ITD between the contralateral and ipsilateral ears was 70 μs for the first dolphin and 118 μs for the second dolphin. While these results provide support for a notable degree of acoustic isolation of the ears for jawphone-delivered stimuli, there are implications for studies involving processes such as sound localization and unilateral hearing loss.
    The Journal of the Acoustical Society of America 09/2014; 136(3):1402. · 1.65 Impact Factor
  • James J Finneran, Jason Mulsow, Dorian S Houser
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    ABSTRACT: Phantom echo generation replaces physical targets with electronic signals that can be delayed in time, scaled in amplitude, and broadcast to an echolocating animal to simulate echoes from distant objects. Compared to physical targets, phantom echoes have the advantages of allowing for instantaneous changes in target characteristics, independent manipulation of echo delay and echo amplitude, and easy randomization of target range. At the Navy Marine Mammal Program in San Diego, California, phantom echo generation is combined with measurements of auditory evoked potentials to investigate the temporal dynamics of biosonar signal emission and reception in bottlenose dolphins. The studies are primarily focused on examining automatic gain control mechanisms by measuring changes in hearing sensitivity - assessed via the auditory steady-state response (ASSR) to an amplitude modulated tone - over time courses corresponding to single biosonar click-echo pairs. Results show the ASSR amplitude initially decreases at the time of click emission and then recovers following click emission, with the time course of recovery related to target range, click amplitude, and tone frequency. Additional studies are focused on dynamic changes in click emissions that occur with changes in target range. [Work funded by SSC Pacific Naval Innovative Science and Engineering (NISE) program.].
    The Journal of the Acoustical Society of America 04/2014; 135(4):2173. · 1.65 Impact Factor
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    ABSTRACT: Dolphins are social animals that rely heavily on passive and active acoustics for communication, navigation, foraging, and detecting predators. Auditory masking, from both natural and anthropogenic noise sources, may adversely affect these fitness-related capabilities. The dolphin's ability to detect a variety of complex signals (both dolphin phonations and tonal signals) masked by Gaussian, comodulated, snapping shrimp, and ice squeaks noise was tested. Detection thresholds were measured using a go/no-go adaptive staircase procedure. Masking patterns were similar for all signals (whistles, burst-pulse, and pure tones) except for click signals. Masking from ice squeaks resulted in the largest masked thresholds, while snapping shrimp and comodulated noise resulted in a release from masking relative to thresholds from Gaussian noise. Click signals were most difficult to detect when masked by snapping shrimp. Recognition thresholds were estimated for whistle-like signals using a cross-modal, matching-to-sample procedure. Recognition thresholds were on average 4 dB greater than detection thresholds for all noise types. The auditory mechanisms governing the results are discussed. [Work supported by the ONR.].
    The Journal of the Acoustical Society of America 04/2014; 135(4):2151. · 1.65 Impact Factor
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    ABSTRACT: It has been proposed that two pairs of phonic lips might be utilized by a dolphin to adaptively manipulate the frequency content and directionality of the echolocation beam in response to acquired target information. The presence of two pulses appearing off-axis of the echolocation beam and separated in time has been proposed as evidence supporting this hypothesis. An array containing 35 hydrophones was used to measure the beam pattern of a bottlenose dolphin performing a phantom echo-change detection task. Simulated target ranges varied from 2.5 to 80 m and clicks were measured at 5-10° resolution from + /150°. At recording angles beyond + /30°, the click appeared as two distinct pulses that declined in amplitude and distorted as the off-axis angle increased. A simple model utilizing the time difference of arrival for the two pulses was used to compare the direct source-receiver path to one of two source-reflector-receiver paths. Assuming a range of constant sound speeds, distances traveled were compared to a CT scan of the same animal to predict anatomical regions potentially contributing to the second pulse. Results suggest that the second pulse is due to reflections from internal structures of the dolphin head and not a second sound source.
    The Journal of the Acoustical Society of America 04/2014; 135(4):2206. · 1.65 Impact Factor
  • Jason Mulsow, Dorian S. Houser, James J. Finneran
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    ABSTRACT: Auditory evoked potential (AEP) measurements are useful for describing the variability of hearing among individuals in marine mammal populations, an important consideration in terms of basic biology and the design of noise mitigation criteria. In this study, hearing thresholds were measured for 16 male California sea lions at frequencies ranging from 0.5 to 32 kHz using the auditory steady state-response (ASSR), a frequency-specific AEP. Audiograms for most sea lions were grossly similar to previously reported psychophysical data in that hearing sensitivity increased with increasing frequency up to a steep reduction in sensitivity between 16 and 32 kHz. Average thresholds were not different from AEP thresholds previously reported for male and female California sea lions. Two sea lions from the current study exhibited abnormal audiograms: a 26-yr-old sea lion had impaired hearing with a high-frequency hearing limit (HFHL) between 8 and 16 kHz, and an 8-yr-old sea lion displayed elevated thresholds across most tested frequencies. The auditory brainstem responses (ABRs) for these two individuals and an additional 26-yr-old sea lion were aberrant compared to those of other sea lions. Hearing loss may have fitness implications for sea lions that rely on sound during foraging and reproductive activities.
    Marine Mammal Science 02/2014; · 2.13 Impact Factor
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    ABSTRACT: In-air anthropogenic sound has the potential to affect grey seal (Halichoerus grypus) behaviour and interfere with acoustic communication. In this study, a new method was used to deliver acoustic signals to grey seals as part of an in-air hearing assessment. Using in-ear headphones with adapted ear inserts allowed for the measurement of auditory brainstem responses (ABR) on sedated grey seals exposed to 5-cycle (2-1-2) tone pips. Thresholds were measured at 10 frequencies between 1-20 kHz. Measurements were made using subcutaneous electrodes on wild seals from the Baltic and North Seas. Thresholds were determined by both visual and statistical approaches (single point F-test) and good agreement was obtained between the results using both methods. The mean auditory thresholds were ≤40 dB re 20 µPa peak equivalent sound pressure level (peSPL) between 4-20 kHz and showed similar patterns to in-air behavioural hearing tests of other phocid seals between 3 and 20 kHz. Below 3 kHz, a steep reduction in hearing sensitivity was observed, which differed from the rate of decline in sensitivity obtained in behavioural studies on other phocids. Differences in the rate of decline may reflect influence of the ear inserts on the ability to reliably transmit lower frequencies or interference from the structure of the distal end of the ear canal.
    PLoS ONE 01/2014; 9(3):e90824. · 3.53 Impact Factor
  • James J Finneran, Jason Mulsow, Dorian S Houser
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    ABSTRACT: The auditory steady-state response (ASSR) to an external tone was measured in an echolocating dolphin to determine if hearing sensitivity changes could be tracked over time scales corresponding to single click-echo pairs. Individual epochs containing click-echo pairs were first extracted from the instantaneous electroencephalogram. Epochs were coherently averaged using the external tone modulation rate as a timing reference, then Fourier transformed using a sliding, 10-ms temporal window to obtain the ASSR amplitude as a function of time. The results revealed a decrease in the ASSR amplitude at the time of click emission, followed by a 25-70 ms recovery.
    The Journal of the Acoustical Society of America 11/2013; 134(5):3913-7. · 1.65 Impact Factor
  • Dorian S Houser, Stephen W Martin, James J Finneran
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    ABSTRACT: Acoustic dose-response functions can be used to explore the relationship between anthropogenic noise exposure and changes in marine mammal behavior. Fifteen sea lions participated in a controlled exposure study to determine the relationship between the received sound pressure level (SPL) of a mid-frequency sonar signal (1-s duration, 3250-3450 Hz) and behavioral deviations from a trained behavior. Sea lions performed 10 control trials followed by 10 exposure trials within an open-water enclosure. Acoustic playbacks occurred once during each exposure trial when the sea lion crossed the middle of the enclosure. Received levels, ranging from 125 to 185 dB re 1 μPa (rms) SPL, were randomly assigned but were consistent across all trials for each individual. Blind scoring of behavioral responses was performed for all trials. A canonical correlation analysis indicated that cessation of the trained behavior, haul-out, a change in respiration rate, and prolonged submergence were reliable response indicators. Sea lions showed both an increased responsiveness and severity of response with increasing received SPL. No habituation to repeated exposures was observed, but age was a significant factor affecting the dose-response relationship. Response patterns and factors affecting behavioral responses were different from those observed in bottlenose dolphins and are indicative of species-specific sensitivities.
    The Journal of the Acoustical Society of America 11/2013; 134(5):4046. · 1.65 Impact Factor
  • Jason Mulsow, James J Finneran, Dorian S Houser
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    ABSTRACT: Studies with some echolocating odontocetes demonstrate that receiver-based automatic gain control (AGC) compensates for reductions in echo strength resulting from acoustic spreading loss. This study examined AGC in an echolocating bottlenose dolphin by measuring changes in hearing sensitivity over time courses corresponding to single click-echo pairs. The electrophysiological auditory steady-state response (ASSR) elicited by a 113-kHz sinusoidally amplitude-modulated tone was recorded while the dolphin performed a target discrimination task. Auditory electrophysiological responses were extracted from the instantaneous electroencephalogram and coherently averaged using the modulation rate of the 113-kHz tone as a reference. A Fourier transform was then performed with a 10-ms sliding window to obtain the ASSR amplitude as a function of time relative to the dolphin's outgoing click and received echo. The ASSR amplitude initially decreased at the time of click emission and then recovered over a course of 25 to 70 ms, depending on target range. This relatively long time course of recovery appears to be consistent with forward-masking, as opposed to an AGC mechanism based on the contraction and gradual release of middle ear muscles coincident with click emission. [Work funded by SSC Pacific Naval Innovative Science and Engineering (NISE) program.].
    The Journal of the Acoustical Society of America 11/2013; 134(5):4119. · 1.65 Impact Factor
  • James J Finneran, Jason Mulsow, Dorian S Houser
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    ABSTRACT: Studies with echolocating odontocetes suggest that forms of automatic gain control mediate auditory electrophysiological responses to target echoes. This study used a phantom echo generator and auditory evoked potential measurements to examine automatic gain control in a bottlenose dolphin. Auditory evoked potentials to outgoing clicks and incoming echoes were recorded for simulated ranges from 2.5 to 80 m. When geometric spreading loss was simulated, echo-evoked potential amplitudes were essentially constant up to 14 m and progressively decreased with increasing range. When the echo levels were held constant relative to clicks, echo-evoked potential amplitudes increased with increasing range up to 80 m. These results suggest that automatic gain control maintains distance-independent echo-evoked potential amplitudes at close range, but does not fully compensate for attenuation due to spreading loss at longer ranges. The automatic gain control process appears to arise from an interaction of transmitter and receiver based processes, resulting in a short-range region of distance-independent echo-evoked potential amplitudes for relevant targets, and a longer-range region in which echo-evoked potential amplitudes are reduced. [Work funded by SSC Pacific Naval Innovative Science and Engineering (NISE) program.].
    The Journal of the Acoustical Society of America 11/2013; 134(5):4120. · 1.65 Impact Factor
  • Dorian S Houser, Stephen W Martin, James J Finneran
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    ABSTRACT: Military sonar has the potential to negatively impact marine mammals. To investigate factors affecting behavioral disruption in California sea lions (Zalophus californianus), fifteen sea lions participated in a controlled exposure study using a simulated tactical sonar signal (1 s duration, 3250-3450 Hz) as a stimulus. Subjects were placed into groups of three and each group received a stimulus exposure of 125, 140, 155, 170, or 185 dB re: 1 μPa (rms). Each subject was trained to swim across an enclosure, touch a paddle, and return to the start location. Sound exposures occurred at the mid-point of the enclosure. Control and exposure sessions were run consecutively and each consisted of ten, 30-s trials. The occurrence and severity of behavioral responses were used to create acoustic dose-response and dose-severity functions. Age of the subject significantly affected the dose-response relationship, but not the dose-severity relationship. Repetitive exposures did not affect the dose-response relationship.
    Marine environmental research 10/2013; · 2.34 Impact Factor
  • James J Finneran
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    ABSTRACT: Dolphin strategies for detecting objects and changes in objects were investigated by having three trained bottlenose dolphins perform long-range echolocation tasks. The tasks featured the use of "phantom" echoes produced by capturing the dolphin's outgoing echolocation clicks, convolving the clicks with the impulse response of a physical target to create an echo waveform, then broadcasting the delayed, scaled echo waveform back to the dolphin. Dolphins were trained to report the presence of phantom echoes or a change in phantom echoes. Target simulated ranges varied from 25 to 800 m. At ranges below 75 m, all dolphins followed a single click-echo paradigm, where inter-click intervals exceeded the two-transit time (i.e., the dolphins waited to receive the echo from a click before emitting the next click). As the range increased beyond 75 m, two of the three dolphins increasingly produced bursts, or "packets," of several clicks, then waited for the packet of echoes to return before emitting another packet of clicks. The third dolphin instead utilized very high click repetition rates. The use of click packets may be a response to a limitation in the dolphin's ability to employ multi-echo processing with large inter-echo delays.
    The Journal of the Acoustical Society of America 05/2013; 133(5):3406. · 1.65 Impact Factor
  • Jason Mulsow, James J Finneran
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    ABSTRACT: Subjective equal-loudness contours are used to create weighting functions for human noise-mitigation criteria. Comparable direct measurements of subjective loudness with animal subjects are, however, difficult to conduct. Using methods similar to those used in previous mammalian studies, this study estimated subjective loudness through the measurement of response time (RT) in an auditory signal-detection task. Measurements were conducted in a sound-attenuating hut with a California sea lion and under water in a quiet pool with a bottlenose dolphin. Tonal stimuli were presented at supra- and near-threshold sound pressure levels (SPLs) using a method of constants. Median RT increased with decreasing SPL for both species across all tested frequencies. A Piéron function, which models RT as a function of SPL, was fitted to the RT-SPL curves in a nonlinear fashion. Equal-latency curves were based on the Piéron functions at each frequency. Preliminary results for the sea lion suggest that the equal-latency curves are similar to the audiogram at longer median RTs (~300 ms), with increasing deviation from the audiogram at the fastest median RTs (~200 ms). Continued testing with additional subjects will provide further data for designing marine mammal auditory weighting functions. [Funded by U.S. Navy Living Marine Resources Program.].
    The Journal of the Acoustical Society of America 05/2013; 133(5):3257. · 1.65 Impact Factor
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    ABSTRACT: Auditory masking occurs when one sound (usually called noise) interferes with the detection, discrimination, or recognition of another sound (usually called the signal). This interference can lead to detriments in a listener's ability to communicate, forage, and navigate. Most studies of auditory masking in marine mammals have been limited to detection thresholds of pure tones in Gaussian noise. Environmental noise marine mammals encounter is often more complex. In the current study, detection thresholds were estimated for bottlenose dolphins with a 10 kHz signal masked by natural, anthropogenic, and synthesized noise. Using a band-widening paradigm, detection thresholds exhibited a pattern where signal thresholds increased proportionally to bandwidth for narrow band noise. However, when noise bandwidth was greater than a critical band, masking patterns diverged. Subsequent experiments demonstrated that the auditory mechanisms responsible for the divergent masking patterns were related to across-channel comparison and within-valley listening.
    The Journal of the Acoustical Society of America 03/2013; 133(3):1811-8. · 1.65 Impact Factor
  • James J Finneran
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    ABSTRACT: When echolocating, dolphins typically emit a single broadband "click," then wait to receive the echo before emitting another click. However, previous studies have shown that during long-range echolocation tasks, they may instead emit a burst, or "packet," of several clicks, then wait for the packet of echoes to return before emitting another packet of clicks. The reasons for the use of packets are unknown. In this study, packet use was examined by having trained bottlenose dolphins perform long-range echolocation tasks. The tasks featured "phantom" echoes produced by capturing the dolphin's outgoing echolocation clicks, convolving the clicks with an impulse response to create an echo waveform, and then broadcasting the delayed, scaled echo to the dolphin. Dolphins were trained to report the presence of phantom echoes or a change in phantom echoes. Target range varied from 25 to 800 m. At ranges below 75 m, the dolphins rarely used packets. As the range increased beyond 75 m, two of the three dolphins increasingly produced packets, while the third dolphin instead utilized very high click repetition rates. The use of click packets appeared to be governed more by echo delay (target range) than echo amplitude.
    The Journal of the Acoustical Society of America 03/2013; 133(3):1796-810. · 1.65 Impact Factor
  • James J Finneran, Carolyn E Schlundt
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    ABSTRACT: Temporary threshold shift (TTS) was measured in two bottlenose dolphins (Tursiops truncatus) after exposure to 16-s tones between 3 and 80 kHz to examine the effects of exposure frequency on the onset, growth, and recovery of TTS. Hearing thresholds were measured approximately one-half octave above the exposure frequency using a behavioral response paradigm featuring an adaptive staircase procedure. Results show frequency-specific differences in TTS onset and growth, and suggest increased susceptibility to auditory fatigue for frequencies between approximately 10 and 30 kHz. Between 3 and 56 kHz, the relationship between exposure frequency and the exposure level required to induce 6 dB of TTS, measured 4 min post-exposure, agrees closely with an auditory weighting function for bottlenose dolphins developed from equal loudness contours [Finneran and Schlundt. (2011). J. Acoust. Soc. Am. 130, 3124-3136].
    The Journal of the Acoustical Society of America 03/2013; 133(3):1819-26. · 1.65 Impact Factor
  • Source
    Brian K Branstetter, James J Finneran
    Animal Communication and Noise, Edited by H. Brumm, 01/2013: chapter 10: pages 273-308; Springer-Verlag.
  • The Journal of the Acoustical Society of America 01/2013; 134(6):4556-4565. · 1.65 Impact Factor

Publication Stats

1k Citations
246.62 Total Impact Points

Institutions

  • 2006–2014
    • Navy's Space and Naval Warfare Systems Command
      San Diego, California, United States
    • Naval Medical Center San Diego
      • Department of Anesthesiology
      San Diego, California, United States
  • 2012–2013
    • National Marine Mammal Foundation
      San Diego, California, United States
  • 2000–2013
    • United States Navy
      • Space and Naval Warfare Systems Center
      Monterey, CA, United States
  • 2008–2012
    • University of Hawaiʻi at Hilo
      Hilo, Hawaii, United States
    • University of Hawai'i System
      Honolulu, Hawaii, United States
  • 2011
    • University of California, Santa Cruz
      • Department of Ocean Sciences
      Santa Cruz, CA, United States
    • Naval Undersea Warfare Center
      Newport, Rhode Island, United States
  • 2000–2004
    • The Ohio State University
      • Department of Mechanical and Aerospace Engineering
      Columbus, OH, United States