Detection of interaural correlation by neurons in the superior olivary complex, inferior colliculus and auditory cortex of the unanesthetized rabbit

Coffey, Charles S.; Ebert, Charles S.; Marshall, Allen F.; Skaggs, John D.; Falk, Stephanie; Crocker, William D.; Pearson, James; Fitzpatrick, Douglas C.

doi:10.1016/j.heares.2006.06.005

Cited by 35 publications

(28 citation statements)

References 64 publications

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“…The concentration of mean interaural phase differences at 0.3 is reminiscent of observations in small mammals (Brand et al 2002;Coffey et al 2006;McAlpine et al 2001;Pecka et al 2008;Yin et al 1986) as well as model predictions based on optimal coding (Harper and McAlpine 2004). These data were interpreted as indicative of a slope-coding mechanism.…”

Section: Implications On Itd Codingsupporting

confidence: 56%

Tuning to Interaural Time Difference and Frequency Differs Between the Auditory Arcopallium and the External Nucleus of the Inferior Colliculus

Vonderschen¹,

Wagner²

2009

Journal of Neurophysiology

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Vonderschen K, Wagner H. Tuning to interaural time difference and frequency differs between the auditory arcopallium and the external nucleus of the inferior colliculus. J Neurophysiol 101: 2348 -2361, 2009. First published March 4, 2009 doi:10.1152/jn.91196.2008. Barn owls process sound-localization information in two parallel pathways, the midbrain and the forebrain pathway. Exctracellular recordings of neural responses to auditory stimuli from far advanced stations of these pathways, the auditory arcopallium in the forebrain and the external nucleus of the inferior colliculus in the midbrain, demonstrated that the representations of interaural time difference and frequency in the forebrain pathway differ from those in the midbrain pathway. Specifically, low-frequency representation was conserved in the forebrain pathway, while it was lost in the midbrain pathway. Variation of interaural time difference yielded symmetrical tuning curves in the midbrain pathway. By contrast, the typical forebraintuning curve was asymmetric with a steep slope crossing zero time difference and a less-steep slope toward larger contralateral time disparities. Low sound frequencies contributed sensitivity to contralateral leading sounds underlying these asymmetries, whereas high frequencies enhanced the steepness of slopes at small interaural time differences. Furthermore, the peaks of time-disparity tuning curves were wider in the forebrain than in the midbrain. The distribution of the steepest slopes of best interaural time differences in the auditory arcopallium, but not in the external nucleus of the inferior colliculus, was centered at zero time difference. The distribution observed in the auditory arocpallium is reminiscent of the situation observed in small mammals. We speculate that the forebrain representation may serve as a population code supporting fine discrimination of central interaural time differences and coarse indication of laterality of a stimulus for large interaural time differences.

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Section: Implications On Itd Codingsupporting

confidence: 56%

Tuning to Interaural Time Difference and Frequency Differs Between the Auditory Arcopallium and the External Nucleus of the Inferior Colliculus

Vonderschen¹,

Wagner²

2009

Journal of Neurophysiology

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“…Instead, we used the nonparametric standard separation metric, D (Sakitt, 1973). This has been used by other investigators in analyzing neuronal thresholds in the inferior colliculus (IC) (Jiang et al, 1997;Shackleton et al, 2003;Coffey et al, 2006). Note, however, that use of dЈ instead of D in the analysis of the data in this study produced virtually identical results in all neurons.…”

Section: Methodsmentioning

confidence: 99%

Interaural Level Difference Discrimination Thresholds for Single Neurons in the Lateral Superior Olive

Tollin¹,

Koka²,

Tsai³

2008

J. Neurosci.

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The lateral superior olive (LSO) is one of the earliest sites in the auditory pathway that is involved in processing acoustical cues to sound location. Here, we tested the hypothesis that LSO neurons can signal small changes in interaural level differences (ILDs), a cue to horizontal sound location, of pure tones based on discharge rate consistent with psychophysical performance in the discrimination of ILDs. Neural thresholds for ILD discrimination were determined from the discharge rates and associated response variability of single units in response to 300 ms tones in the LSO of barbiturate-anesthetized cats using detection theory. Neural response variability was well described by a power function of the mean rate, both in individual neurons and collectively; LSO neurons were less variable than expected from a Poisson process. Compared with psychophysical data, the best-threshold ILDs of single LSO neurons were comparable with or better than behavior over the full range of frequencies (0.3-35 kHz) and pedestal ILDs (Ϯ25 dB) explored in this study. With a pedestal ILD of 0 dB, ILD increments of 1 dB could be discriminated by some neurons, with a median of 4.35 dB across neurons. For pedestal ILDs away from 0 dB, the best-threshold ILDs were as low as 0.5 dB, with a median of 2.3 dB. These findings support the hypothesis that the LSO plays a role in the extraction of ILD, and that the representation of ILD by LSO neurons may set a lower bound on the behavioral sensitivity to ILDs.

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“…In animals where sound localization is critical and available from the neural circuits, it can be used in that way. If not, the general neural architecture still supports adequate sensitivity to sound location, and in addition provides for increased separation of signals from noise and a sensitivity to auditory "spaciousness" through variations in the responses to interaural correlation (Yin et al, 1987;Shackleton et al, 2005;Coffey et al, 2006) In humans using broadband stimuli, there is a gradual increase in thresholds within the physiological range as the sound becomes increasingly lateralized towards the ear. Measurements of this increase range from about a factor of two with clicks (Hafter et al, 1975) up to a factor of about four with noise (Klumpp and Eady, 1957;Mossop and Culling, 1998).…”

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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Detection of interaural correlation by neurons in the superior olivary complex, inferior colliculus and auditory cortex of the unanesthetized rabbit

Cited by 35 publications

References 64 publications

Tuning to Interaural Time Difference and Frequency Differs Between the Auditory Arcopallium and the External Nucleus of the Inferior Colliculus

Tuning to Interaural Time Difference and Frequency Differs Between the Auditory Arcopallium and the External Nucleus of the Inferior Colliculus

Interaural Level Difference Discrimination Thresholds for Single Neurons in the Lateral Superior Olive

Behavioral sensitivity to interaural time differences in the rabbit

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