Effect of Arrival Time on Stereophonic Localization

Snow, William B.

doi:10.1121/1.1928001

Cited by 10 publications

(18 citation statements)

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“…Furthermore, Yin found that increasing the sound level of the lagging click would shift the ISI response curve, as though a source was now closer to the louder, lagging sound. This time-intensity trade is also seen in human summing localization (Snow, 1954).…”

Section: Comparisons With Other Neurophysiological Studiesmentioning

confidence: 72%

“…Our results suggest that in the owl at least, the similarity between the ISI and single-speaker functions depends on the same use of a binaural cross-correlation-like mechanism whether there is one source or more than one. This idea may be extended to the time-intensity trade in which the perceived locus of a target in summing localization can be biased toward the louder source (Snow, 1954). In an earlier study, we demonstrated that when the sounds of two speakers are produced simultaneously and are identical except for overall amplitude, the neural image on the space map is biased toward the louder speaker (Takahashi and Keller, 1994).…”

Section: Comparisons With Other Neurophysiological Studiesmentioning

confidence: 99%

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Binaural Cross-Correlation Predicts the Responses of Neurons in the Owl’s Auditory Space Map under Conditions Simulating Summing Localization

Keller

Takahashi

1996

J. Neurosci.

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Summing localization describes the perceptions of human listeners to two identical sounds from different locations presented with delays of 0 -1 msec. Usually a single source is perceived to be located between the two actual source locations, biased toward the earlier source. We studied neuronal responses within the space map of the barn owl to sounds presented with this same paradigm. The owl's primary cue for localization along the azimuth, interaural time difference (ITD), is based on a cross-correlation-like treatment of the signals arriving at each ear. The output of this cross-correlation is displayed as neural activity across the auditory space map in the external nucleus of the owl's inferior colliculus. Because the ear input signals reflect the physical summing of the signals generated by each speaker, we first recorded the sounds at each ear and computed their cross-correlations at various interstimulus delays. The resulting binaural cross-correlation surface strongly resembles the pattern of activity across the space map inferred from recordings of single space-specific neurons. Four peaks are observed in the cross-correlation surface for any nonzero delay. One peak occurs at the correlation delay equal to the ITD of each speaker. Two additional peaks reflect "phantom sources" occurring at correlation delays that match the signal of the left speaker in one ear with the signal of the right speaker in the other ear. At zero delay, the two phantom peaks coincide. The surface features are complicated further by the interactions of the various correlation peaks.

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Section: Comparisons With Other Neurophysiological Studiesmentioning

confidence: 72%

Section: Comparisons With Other Neurophysiological Studiesmentioning

confidence: 99%

Binaural Cross-Correlation Predicts the Responses of Neurons in the Owl’s Auditory Space Map under Conditions Simulating Summing Localization

Keller

Takahashi

1996

J. Neurosci.

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“…In a simple case, when two sources emitting identical sounds differ only by their interaural phase difference (IPD), within each frequency band, the resultant binaural cues are the average of those of the individual sources. If the overall amplitude of one source is altered, without changing the spectral profile, the IPD is biased toward the more-intense source (Snow, 1954;Bauer, 1961;Blauert, 1997). If, on the other hand, one source is phase-advanced or phase-delayed relative to the other source, the ILD is biased toward the lagging source (Snow, 1954;Bauer, 1961;Blauert, 1997).…”

Section: Analysis Of the Modelmentioning

confidence: 99%

“…If the overall amplitude of one source is altered, without changing the spectral profile, the IPD is biased toward the more-intense source (Snow, 1954;Bauer, 1961;Blauert, 1997). If, on the other hand, one source is phase-advanced or phase-delayed relative to the other source, the ILD is biased toward the lagging source (Snow, 1954;Bauer, 1961;Blauert, 1997). When the relative phase and amplitude of the source both differ, these differences between the sources are each reflected in changes in both the ILD and IPD (Bauer, 1961).…”

Section: Analysis Of the Modelmentioning

confidence: 99%

Localization and Identification of Concurrent Sounds in the Owl's Auditory Space Map

Keller¹,

Takahashi²

2005

J. Neurosci.

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In nature, sounds from multiple sources sum at the eardrums, generating complex cues for sound localization and identification. In this clutter, the auditory system must determine "what is where." We examined this process in the auditory space map of the barn owl's (Tyto alba) inferior colliculus using two spatially separated sources simultaneously emitting uncorrelated noise bursts, which were uniquely identified by different frequencies of sinusoidal amplitude modulation. Spatial response profiles of isolated neurons were constructed by testing the source-pair centered at various locations in virtual auditory space. The neurons responded whenever a source was placed within the receptive field, generating two clearly segregated foci of activity at appropriate loci. The spike trains were locked strongly to the amplitude modulation of the source within the receptive field, whereas the other source had minimal influence. Two sources amplitude modulated at the same rate were resolved successfully, suggesting that source separation is based on differences of fine structure. The spike rate and synchrony were stronger for whichever source had the stronger average binaural level. A computational model showed that neuronal activity was primarily proportional to the degree of matching between the momentary binaural cues and the preferred values of the neuron. The model showed that individual neurons respond to and synchronize with sources in their receptive field if there are frequencies having an average binaural-level advantage over a second source. Frequencies with interaural phase differences that are shared by both sources may also evoke activity, which may be synchronized with the amplitude modulations from either source.

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“…The fused image falls between the two source locations and is biased toward the location of the leading sound. The presence of an inter-stimulus level difference (ISLD) also affects localization: at a given ISD, the location judgement is biased toward the more intense loudspeaker (Snow 1954). It follows that the shift due to an ISD can be compensated by applying an opposing ISLD-this balanc-ing of ISD and ISLD has been termed time-intensity trading.…”

mentioning

confidence: 99%

Responses of Auditory Cortical Neurons to Pairs of Sounds: Correlates of Fusion and Localization

Mickey

Middlebrooks

2001

Journal of Neurophysiology

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Mickey, Brian J. and John C. Middlebrooks. Responses of auditory cortical neurons to pairs of sounds: correlates of fusion and localization. J Neurophysiol 86: [1333][1334][1335][1336][1337][1338][1339][1340][1341][1342][1343][1344][1345][1346][1347][1348][1349][1350] 2001. When two brief sounds arrive at a listener's ears nearly simultaneously from different directions, localization of the sounds is described by "the precedence effect." At inter-stimulus delays (ISDs) Ͻ5 ms, listeners typically report hearing not two sounds but a single fused sound. The reported location of the fused image depends on the ISD. At ISDs of 1-4 ms, listeners point near the leading source (localization dominance). As the ISD is decreased from 0.8 to 0 ms, the fused image shifts toward a location midway between the two sources (summing localization). When an inter-stimulus level difference (ISLD) is imposed, judgements shift toward the more intense source. Spatial hearing, including the precedence effect, is thought to depend on the auditory cortex. Therefore we tested the hypothesis that the activity of cortical neurons signals the perceived location of fused pairs of sounds. We recorded the unit responses of cortical neurons in areas A1 and A2 of anesthetized cats. Single broadband clicks were presented from various frontal locations. Paired clicks were presented with various ISDs and ISLDs from two loudspeakers located 50°to the left and right of midline. Units typically responded to single clicks or paired clicks with a single burst of spikes. Artificial neural networks were trained to recognize the spike patterns elicited by single clicks from various locations. The trained networks were then used to identify the locations signaled by unit responses to paired clicks. At ISDs of 1-4 ms, unit responses typically signaled locations near that of the leading source in agreement with localization dominance. Nonetheless the responses generally exhibited a substantial undershoot; this finding, too, accorded with psychophysical measurements. As the ISD was decreased from ϳ0.4 to 0 ms, network estimates typically shifted from the leading location toward the midline in agreement with summing localization. Furthermore a superposed ISLD shifted network estimates toward the more intense source, reaching an asymptote at an ISLD of 15-20 dB. To allow quantitative comparison of our physiological findings to psychophysical results, we performed human psychophysical experiments and made acoustical measurements from the ears of cats and humans. After accounting for the difference in head size between cats and humans, the responses of cortical units usually agreed with the responses of human listeners, although a sizable minority of units defied psychophysical expectations.

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Effect of Arrival Time on Stereophonic Localization

Cited by 10 publications

References 0 publications

Binaural Cross-Correlation Predicts the Responses of Neurons in the Owl’s Auditory Space Map under Conditions Simulating Summing Localization

Binaural Cross-Correlation Predicts the Responses of Neurons in the Owl’s Auditory Space Map under Conditions Simulating Summing Localization

Localization and Identification of Concurrent Sounds in the Owl's Auditory Space Map

Responses of Auditory Cortical Neurons to Pairs of Sounds: Correlates of Fusion and Localization

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