Localization of brief sounds: Effects of level and background noise

Macpherson, Ewan A.; Middlebrooks, John C.

doi:10.1121/1.1310196

Cited by 71 publications

(78 citation statements)

References 31 publications

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“…Closely related to the perceptional accomplishment of signal detection is the localization of stimuli. Similar to the improved detection in noise, a prolongation of brief sounds can considerably improve their localization (Hofman and van Opstal, 1998;Macpherson and Middlebrooks, 2000). Since marmosets live in forests where visibility is limited, maintaining a sufficient locatability of calls may be crucial for the animals when signalling their position to group mates.…”

Section: Discussionmentioning

confidence: 99%

Acoustic communication in noise: regulation of call characteristics in a New World monkey

Brumm

Voß

Köllmer

et al. 2004

Journal of Experimental Biology

312

208

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This study on common marmosets Callithrix jacchus is the first to examine noise-dependent mechanisms of vocal plasticity in a New World monkey. Since acoustic communication can be considerably impaired by environmental noise, some animals have evolved adaptations to counteract its masking effects. The studied marmosets increased the sound level of their spontaneous calls in response to increased levels of white noise broadcast to them. Possibly, such noise-dependent adjustment of vocal amplitude serves to maintain a specific signal-to-noise ratio that is favourable for signal production. Concurrently, the adjustment of vocal amplitude can maintain a given active space for communication. In contrast to some bird species, no noiseinduced increase in the number of syllables per call series could be found, showing that an increased serial redundancy of vocal signals was not used to communicate under noisy conditions. Finally, we examined a possible noise-dependent prolongation of vocal signals. This approach was guided by the findings of perceptional studies, which suggest an increased detection probability of prolonged signals in noise by temporal summation. Marmosets indeed increased the duration of their call syllables along with increasing background noise levels. This is the first evidence of such mechanism of vocal plasticity in an animal communication system.

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Section: Discussionmentioning

confidence: 99%

Acoustic communication in noise: regulation of call characteristics in a New World monkey

Brumm

Voß

Köllmer

et al. 2004

Journal of Experimental Biology

312

208

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“…For shorter sound durations, the elevation gain decreases systematically with either decreasing stimulus duration (Hofman and Van Opstal, 1998;Vliegen and Van Opstal, 2004) or increasing stimulus level (MacPherson and Middlebrooks, 2000;Vliegen and Van Opstal, 2004). The former phenomenon was proposed to be attributable to a neural integration process that improves its elevation estimate by accumulating spectral evidence about the current HRTF through consecutive short-term (few milliseconds) "looks" at the acoustic input.…”

Section: Short-versus Long-duration Soundsmentioning

confidence: 99%

Dynamic Sound Localization during Rapid Eye-Head Gaze Shifts

Vliegen¹,

Grootel²,

Opstal³

2004

J. Neurosci.

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Human sound localization relies on implicit head-centered acoustic cues. However, to create a stable and accurate representation of sounds despite intervening head movements, the acoustic input should be continuously combined with feedback signals about changes in head orientation. Alternatively, the auditory target coordinates could be updated in advance by using either the preprogrammed gaze-motor command or the sensory target coordinates to which the intervening gaze shift is made ("predictive remapping"). So far, previous experiments cannot dissociate these alternatives. Here, we study whether the auditory system compensates for ongoing saccadic eye and head movements in two dimensions that occur during target presentation. In this case, the system has to deal with dynamic changes of the acoustic cues as well as with rapid changes in relative eye and head orientation that cannot be preprogrammed by the audiomotor system. We performed visual-auditory double-step experiments in two dimensions in which a brief sound burst was presented while subjects made a saccadic eye-head gaze shift toward a previously flashed visual target. Our results show that localization responses under these dynamic conditions remain accurate. Multiple linear regression analysis revealed that the intervening eye and head movements are fully accounted for. Moreover, elevation response components were more accurate for longer-duration sounds (50 msec) than for extremely brief sounds (3 msec), for all localization conditions. Taken together, these results cannot be explained by a predictive remapping scheme. Rather, we conclude that the human auditory system adequately processes dynamically varying acoustic cues that result from self-initiated rapid head movements to construct a stable representation of the target in world coordinates. This signal is subsequently used to program accurate eye and head localization responses.

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“…Under normal binaural hearing the difference cues dominate entirely because azimuth localization is robust against large variations in sound level and SNRs (e.g., Fig. 3, A-C; see also Good and Gilkey 1996;Hofman and Van Opstal 1998;MacPherson and Middlebrooks 2000;Van Wanrooij and Van Opstal 2005;Vliegen and Van Opstal 2004;Zwiers et al 2001) and does not depend on the integrity of the spectral cues (Hofman and Van Opstal 2003;Morimoto 2001;Oldfield and Parker 1984;Van Wanrooij and Van Opstal 2005;Wightman and Kistler 1997).…”

Section: Spectral Cues For Azimuthmentioning

confidence: 99%

“…Experimental manipulations can considerably degrade elevation localization performance, whereas azimuth localization is far more robust: e.g., by inserting molds, either binaurally (Hofman et al 1998;Oldfield and Parker 1984) or monaurally (Hofman and Van Opstal 2003;Morimoto 2001;Van Wanrooij and Van Opstal 2005), by introducing background noise (Good and Gilkey 1996;Zwiers et al 2001) or by extensively varying sound levels and sound duration (Hartmann and Rakerd 1993;Hofman and Van Opstal 1998;MacPherson and Middlebrooks 2000;Vliegen and Van Opstal 2004).…”

Section: Introductionmentioning

confidence: 99%

Sound Localization Under Perturbed Binaural Hearing

Wanrooij

Opstal²

2007

Journal of Neurophysiology

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Van Wanrooij MM, Van Opstal AJ. Sound localization under perturbed binaural hearing. J Neurophysiol 97: [715][716][717][718][719][720][721][722][723][724][725][726] 2007. First published October 25, 2006; doi:10.1152/jn.00260.2006. This paper reports on the acute effects of a monaural plug on directional hearing in the horizontal (azimuth) and vertical (elevation) planes of human listeners. Sound localization behavior was tested with rapid headorienting responses toward brief high-pass filtered (Ͼ3 kHz; HP) and broadband (0.5-20 kHz; BB) noises, with sound levels between 30 and 60 dB, A-weighted (dBA). To deny listeners any consistent azimuth-related head-shadow cues, stimuli were randomly interleaved. A plug immediately degraded azimuth performance, as evidenced by a sound level-dependent shift ("bias") of responses contralateral to the plug, and a level-dependent change in the slope of the stimulus-response relation ("gain"). Although the azimuth bias and gain were highly correlated, they could not be predicted from the plug's acoustic attenuation. Interestingly, listeners performed best for low-intensity stimuli at their normal-hearing side. These data demonstrate that listeners rely on monaural spectral cues for sound-source azimuth localization as soon as the binaural difference cues break down. Also the elevation response components were affected by the plug: elevation gain depended on both stimulus azimuth and on sound level and, as for azimuth, localization was best for low-intensity stimuli at the hearing side. Our results show that the neural computation of elevation incorporates a binaural weighting process that relies on the perceived, rather than the actual, sound-source azimuth. It is our conjecture that sound localization ensues from a weighting of all acoustic cues for both azimuth and elevation, in which the weights may be partially determined, and rapidly updated, by the reliability of the particular cue.

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Localization of brief sounds: Effects of level and background noise

Cited by 71 publications

References 31 publications

Acoustic communication in noise: regulation of call characteristics in a New World monkey

Acoustic communication in noise: regulation of call characteristics in a New World monkey

Dynamic Sound Localization during Rapid Eye-Head Gaze Shifts

Sound Localization Under Perturbed Binaural Hearing

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