Prediction of auditory spatial acuity from neural images on the owl's auditory space map

Bala, Avinash D. S.; Spitzer, M.; Takahashi, Terry T.

doi:10.1038/nature01835

Cited by 87 publications

(81 citation statements)

References 28 publications

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“…A further possible complication of level in bilateral cochlear implants is hypersynchronization to amplitude modulation for high carrier pulse rates (Litvak et al 2001;. Processing of ITDs is typically done by neurons that are broadly-tuned to ITDs using a population code, rather than by narrowly tuned elements (Fitzpatrick et al 1997;McAlpine et al 2001;Bala et al 2003). Decreasing the range of ITDs over which neurons can show a graded response could disrupt the operation of this population code.…”

Section: Effects Of Sound Intensitymentioning

confidence: 99%

Neural and Behavioral Sensitivity to Interaural Time Differences Using Amplitude Modulated Tones with Mismatched Carrier Frequencies

Blanks

Roberts

Buss

et al. 2007

JARO

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Bilateral cochlear implantation is intended to provide the advantages of binaural hearing, including sound localization and better speech recognition in noise. In most modern implants, temporal information is carried by the envelope of pulsatile stimulation, and thresholds to interaural time differences (ITDs) are generally high compared to those obtained in normal hearing observers. One factor thought to influence ITD sensitivity is the overlap of neural populations stimulated on each side. The present study investigated the effects of acoustically stimulating bilaterally mismatched neural populations in two related paradigms: rabbit neural recordings and human psychophysical testing. The neural coding of interaural envelope timing information was measured in recordings from neurons in the inferior colliculus of the unanesthetized rabbit. Binaural beat stimuli with a 1-Hz difference in modulation frequency were presented at the best modulation frequency and intensity as the carrier frequencies at each ear were varied. Some neurons encoded envelope ITDs with carrier frequency mismatches as great as several octaves. The synchronization strength was typically nonmonotonically related to intensity. Psychophysical data showed that human listeners could also make use of binaural envelope cues for carrier mismatches of up to 2-3 octaves. Thus, the physiological and psychophysical data were broadly consistent, and suggest that bilateral cochlear implants should provide information sufficient to detect envelope ITDs even in the face of bilateral mismatch in the neural populations responding to stimulation. However, the strongly nonmonotonic synchronization to envelope ITDs suggests that the limited dynamic range with electrical stimulation may be an important consideration for ITD encoding.

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Section: Effects Of Sound Intensitymentioning

confidence: 99%

Neural and Behavioral Sensitivity to Interaural Time Differences Using Amplitude Modulated Tones with Mismatched Carrier Frequencies

Blanks

Roberts

Buss

et al. 2007

JARO

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“…However, there is a possible neural explanation for the increase in threshold when the physiological range is exceeded, at least in rabbits. At the peaks of the ITD curves the response variability is greater and the change to a small change in ITD is less than on the steepest slope (also see Bala et al, 2003;Shackleton et al, 2003). Most neural tuning curves in the rabbit show a peak in the range of 100-300 μs (Kuwada et al, 1987).…”

Section: Comparison With Neural Thresholdsmentioning

confidence: 99%

Behavioral sensitivity to interaural time differences in the rabbit

et al. 2008

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An important cue for sound localization and separation of signals from noise is the interaural time difference (ITD). Humans are able to localize sounds within 1-2° and can detect very small changes in the ITD (10-20 μs). In contrast, many animals localize sounds with less precision than humans. Rabbits, for example, have sound localization thresholds of ~22°. There is only limited information about behavioral ITD discrimination in animals with poor sound localization acuity that are typically used for the neural recordings. For this study, we measured behavioral discrimination of ITDs in the rabbit for a range of reference ITDs from 0 to ± 300 μs. The behavioral task was conditioned avoidance and the stimulus was band-limited noise (500-1500 Hz). Across animals, the average discrimination threshold was 50-60 μs for reference ITDs of 0 to ± 200 μs. There was no trend in the thresholds across this range of reference ITDs. For a reference ITD of ± 300 μs, which is near the limit of the physiological window defined by the head width in this species, the discrimination threshold increased to ~100 μs. The ITD discrimination in rabbits less acute than in cats, which have a similar head size. This result supports the suggestion that ITD discrimination, like sound localization (see Heffner, 1997, Acta Otolaryngol Suppl 532:46-53, 1997) is determined by factors other than head size.

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“…The surgical procedures for the physiological experiments on owls have been described in detail previously and the data analyzed here have also been analyzed in previous work (Keller and Takahashi, 2000;Bala et al, 2003). Briefly, adult barn owls were anesthetized by intramuscular injections of ketamine (0.05-0.1 ml/h; 100 mg/ml) and diazepam (0.025-0.05 ml/h; 5 mg/ml) and given a prophylactic dosage of ampicillin (0.2 ml, i.m.…”

Section: Physiological Experimentsmentioning

confidence: 99%

“…As a basis for comparison with the gerbil, we also analyzed responses to noise bursts at different ITDs from the exterior nucleus of the ICx in anesthetized barn owls (n ϭ 58 with significant ITD tuning). While there are many important anatomical and physiological differences between the central nucleus of the mammalian IC and the avian ICx, the barn owl ICx responses, in which the representation of ITDs is known to be sparsely distributed across the population (Knudsen and Konishi, 1978;Bala et al, 2003), provide a clear example with which to compare the gerbil responses. The ability of barn owls to localize sounds in the azimuthal plane has been well studied , and it has been shown that this ability relies almost exclusively on sensitivity to ITDs (Poganiatz et al, 2001).…”

Section: Decoding Gerbil and Barn Owl Population Responses To A Hypotmentioning

confidence: 99%

Population Coding of Interaural Time Differences in Gerbils and Barn Owls

Lesica¹,

Lingner²,

Grothe³

2010

J. Neurosci.

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Interaural time differences (ITDs) are the primary cue for the localization of low-frequency sound sources in the azimuthal plane. For decades, it was assumed that the coding of ITDs in the mammalian brain was similar to that in the avian brain, where information is sparsely distributed across individual neurons, but recent studies have suggested otherwise. In this study, we characterized the representation of ITDs in adult male and female gerbils. First, we performed behavioral experiments to determine the acuity with which gerbils can use ITDs to localize sounds. Next, we used different decoders to infer ITDs from the activity of a population of neurons in central nucleus of the inferior colliculus. These results show that ITDs are not represented in a distributed manner, but rather in the summed activity of the entire population. To contrast these results with those from a population where the representation of ITDs is known to be sparsely distributed, we performed the same analysis on activity from the external nucleus of the inferior colliculus of adult male and female barn owls. Together, our results support the idea that, unlike the avian brain, the mammalian brain represents ITDs in the overall activity of a homogenous population of neurons within each hemisphere.

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Prediction of auditory spatial acuity from neural images on the owl's auditory space map

Cited by 87 publications

References 28 publications

Neural and Behavioral Sensitivity to Interaural Time Differences Using Amplitude Modulated Tones with Mismatched Carrier Frequencies

Neural and Behavioral Sensitivity to Interaural Time Differences Using Amplitude Modulated Tones with Mismatched Carrier Frequencies

Behavioral sensitivity to interaural time differences in the rabbit

Population Coding of Interaural Time Differences in Gerbils and Barn Owls

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