Neural Mechanisms of Encoding Binaural Localization Cues in the Auditory Brainstem

Yin, Tom C. T.

doi:10.1007/978-1-4757-3654-0_4

Cited by 159 publications

(136 citation statements)

References 228 publications

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“…Interaural level differences (ILDs) arise from the head shadow effect and functions at high frequencies (Ͼ3 kHz). Both cues are processed by independent brainstem pathways that involve the medial and lateral superior olive, respectively (Yin, 2002). Interestingly, imposing a conflicting ILD in combination with a given ITD under dichotic listening induces a weighted-averaged intracranial location (time-intensity trade-off).…”

Section: Averaging and Bimodality In The Auditory Systemmentioning

confidence: 99%

Pinna Cues Determine Orienting Response Modes to Synchronous Sounds in Elevation

Bremen¹,

Wanrooij²,

Opstal³

2010

J. Neurosci.

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To program a goal-directed orienting response toward a sound source embedded in an acoustic scene, the audiomotor system should detect and select the target against a background. Here, we focus on whether the system can segregate synchronous sounds in the midsagittal plane (elevation), a task requiring the auditory system to dissociate the pinna-induced spectral localization cues. Human listeners made rapid head-orienting responses toward either a single sound source (broadband buzzer or Gaussian noise) or toward two simultaneously presented sounds (buzzer and noise) at a wide variety of locations in the midsagittal plane. In the latter case, listeners had to orient to the buzzer (target) and ignore the noise (nontarget). In the single-sound condition, localization was accurate. However, in the double-sound condition, response endpoints depended on relative sound level and spatial disparity. The loudest sound dominated the responses, regardless of whether it was the target or the nontarget. When the sounds had about equal intensities and their spatial disparity was sufficiently small, endpoint distributions were well described by weighted averaging. However, when spatial disparities exceeded ϳ45°, response endpoint distributions became bimodal. Similar response behavior has been reported for visuomotor experiments, for which averaging and bimodal endpoint distributions are thought to arise from neural interactions within retinotopically organized visuomotor maps. We show, however, that the auditory-evoked responses can be well explained by the idiosyncratic acoustics of the pinnae. Hence basic principles of target representation and selection for audition and vision appear to differ profoundly.

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Section: Averaging and Bimodality In The Auditory Systemmentioning

confidence: 99%

Pinna Cues Determine Orienting Response Modes to Synchronous Sounds in Elevation

Bremen¹,

Wanrooij²,

Opstal³

2010

J. Neurosci.

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“…The cats in the present study localized sounds via gaze shifts, which requires coordination between the neural representation of auditory space and the motor systems controlling eye and head movements . Localization errors may therefore result from any of several causes, including intrinsic properties of the auditory system (Rayleigh, 1907;Stevens and Newman, 1936;Yin, 2002), ambiguity in the encoding of spatial cues (Wallach, 1939;Oldfield and Parker, 1984), a mismatch between the auditory and visual systems (Knudsen and Knudsen, 1985;Zwiers et al, 2003) and/or limitations of the oculomotor system. While it is possible that biases in absolute location estimates largely result from motor effects, it seems at least equally plausible that the computation and representation of acoustic spatial cues are inherently imperfect.…”

Section: Relating Behavioral Measures To Neural Mechanismsmentioning

confidence: 99%

Can measures of sound localization acuity be related to the precision of absolute location estimates?

2008

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Studies of sound localization use relative or absolute psychoacoustic paradigms. Relative tasks assess acuity by determining the smallest angle separating two sources that subjects can discriminate, the minimum audible angle (MAA), whereas absolute tasks measure subjects' abilities to indicate sound location. It is unclear whether or how measures from the two tasks are related, though the belief that the MAA is specifically related to the precision of absolute localization is common. The present study aimed to investigate the basis of this relationship by comparing the precision of absolute location estimates with a measure of spatial acuity computed from the same data. Three cats were trained to indicate apparent sound source locations that varied in azimuth and elevation via orienting gaze shifts (combined eye and head movements). The precision of these absolute responses, as measured by their standard deviation, was compared with acuity thresholds derived from receiver operating characteristic (ROC) analyses of the cumulative distributions. Surprisingly, the acuity measures were occasionally very poor indicators of absolute localization precision. Incongruent results were attributed to errors in mean accuracy, which are disregarded in analyses of traditional relative tasks. Discussion focuses on the potential for internal biases to affect measures of localization acuity.

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“…In the auditory pathway, information about the ITD and ILD is processed initially by separate nuclei, namely, the medial and lateral superior olives, respectively [14]. Both of the nuclei have tonotopic structures, indicating frequency-by-frequency processing.…”

Section: Discussionmentioning

confidence: 99%

Insensitivity to the coherence of interaural-time-difference modulation across frequency channels

Furukawa¹,

Nishida

Kondo³

et al. 2013

Acoust. Sci. & Tech.

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The present study examined the dynamic properties of the across-frequency integration mechanism, specifically the extent to which the information about the direction of changes in the interaural-time difference (ITD) is integrated or compared across frequencies. The stimulus was a complex tone consisting of two sinusoidal carriers, one at 400 and the other at 700 Hz. A sinusoidal modulation in the ITD was imposed on one carrier alone or the two carriers simultaneously. The ITD of each carrier was centered at 0 ms, and the modulation started and ended with the zero phase. ITD modulations, when imposed on the two carriers simultaneously, were in-phase or anti-phase between them. Experiment 1 measured the threshold modulation depth for detecting the modulation with an adaptive method. The thresholds were generally lower when both carriers were modulated than when only one was, indicating across-frequency integration of the information about the presence of modulation. The threshold, however, was not significantly different between the in-phase and antiphase conditions, even when the modulation rate was as low as 1 Hz. Experiment 2 measured the discriminability between in-phase and anti-phase modulations. Modulation depth was fixed at a suprathreshold value (600 ms). The performance varied largely among the listeners, and it was near the chance level for half of listeners even for a 1-Hz rate. The study failed to present compelling evidence that the auditory system is sensitive to the relative phase of ITD modulations for the conditions tested. This suggests that the directional information of even slow ($1 Hz) ITD modulation is not combined effectively across frequencies, at least for the conditions tested.

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Neural Mechanisms of Encoding Binaural Localization Cues in the Auditory Brainstem

Cited by 159 publications

References 228 publications

Pinna Cues Determine Orienting Response Modes to Synchronous Sounds in Elevation

Pinna Cues Determine Orienting Response Modes to Synchronous Sounds in Elevation

Can measures of sound localization acuity be related to the precision of absolute location estimates?

Insensitivity to the coherence of interaural-time-difference modulation across frequency channels

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