Linear coding of complex sound spectra by discharge rate by neurons of the medial nucleus of the trapezoidal body (MNTB) and thier inputs
The interaural level difference (ILD) cue to sound location is first encoded in the lateral superior olive (LSO). ILD sensitivity results because the LSO receives excitatory input from the ipsilateral cochlear nucleus and inhibitory input indirectly from the contralateral cochlear nucleus via glycin...
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2014-12-01
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| Series: | Frontiers in Neural Circuits |
| Subjects: | |
| Online Access: | http://journal.frontiersin.org/Journal/10.3389/fncir.2014.00144/full |
| _version_ | 1828350185367928832 |
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| author | Daniel J Tollin Kanthaiah eKoka |
| author_facet | Daniel J Tollin Kanthaiah eKoka |
| author_sort | Daniel J Tollin |
| collection | DOAJ |
| description | The interaural level difference (ILD) cue to sound location is first encoded in the lateral superior olive (LSO). ILD sensitivity results because the LSO receives excitatory input from the ipsilateral cochlear nucleus and inhibitory input indirectly from the contralateral cochlear nucleus via glycinergic neurons of the ipsilateral medial nucleus of the trapezoid body (MNTB). It is hypothesized that in order for LSO neurons to encode ILDs, the sound spectra at both ears must be accurately encoded via spike rate by their afferents. This spectral-coding hypothesis has not been directly tested in MNTB, likely because MNTB neurons have been mostly described and studied recently in regards to their abilities to encode temporal aspects of sounds, not spectral. Here, we test the hypothesis that MNTB neurons and their inputs from the cochlear nucleus and auditory nerve code sound spectra via discharge rate. The Random Spectral Shape method was used to estimate how the levels of 100-ms duration spectrally stationary stimuli were weighted, both linearly and non- linearly, across a wide band of frequencies. In general, MNTB neurons and their globular bushy cell inputs, were found to be well-modeled by a linear weighting of spectra demonstrating that the pathways through the MNTB can accurately encode sound spectra including those resulting from the acoustical cues to sound location provided by head-related directional transfer functions. Together with the anatomical and biophysical specializations for timing in the MNTB-LSO complex, these mechanisms may allow ILDs to be computed for complex stimuli with rapid spectrotemporally-modulated envelopes such as speech and animal vocalizations and moving sound sources. |
| first_indexed | 2024-04-14T01:21:18Z |
| format | Article |
| id | doaj.art-15245fd4afcb49998c031b902f694080 |
| institution | Directory Open Access Journal |
| issn | 1662-5110 |
| language | English |
| last_indexed | 2024-04-14T01:21:18Z |
| publishDate | 2014-12-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Neural Circuits |
| spelling | doaj.art-15245fd4afcb49998c031b902f6940802022-12-22T02:20:38ZengFrontiers Media S.A.Frontiers in Neural Circuits1662-51102014-12-01810.3389/fncir.2014.00144118841Linear coding of complex sound spectra by discharge rate by neurons of the medial nucleus of the trapezoidal body (MNTB) and thier inputsDaniel J Tollin0Kanthaiah eKoka1University of Colorado School of MedicineUniversity of Colorado School of MedicineThe interaural level difference (ILD) cue to sound location is first encoded in the lateral superior olive (LSO). ILD sensitivity results because the LSO receives excitatory input from the ipsilateral cochlear nucleus and inhibitory input indirectly from the contralateral cochlear nucleus via glycinergic neurons of the ipsilateral medial nucleus of the trapezoid body (MNTB). It is hypothesized that in order for LSO neurons to encode ILDs, the sound spectra at both ears must be accurately encoded via spike rate by their afferents. This spectral-coding hypothesis has not been directly tested in MNTB, likely because MNTB neurons have been mostly described and studied recently in regards to their abilities to encode temporal aspects of sounds, not spectral. Here, we test the hypothesis that MNTB neurons and their inputs from the cochlear nucleus and auditory nerve code sound spectra via discharge rate. The Random Spectral Shape method was used to estimate how the levels of 100-ms duration spectrally stationary stimuli were weighted, both linearly and non- linearly, across a wide band of frequencies. In general, MNTB neurons and their globular bushy cell inputs, were found to be well-modeled by a linear weighting of spectra demonstrating that the pathways through the MNTB can accurately encode sound spectra including those resulting from the acoustical cues to sound location provided by head-related directional transfer functions. Together with the anatomical and biophysical specializations for timing in the MNTB-LSO complex, these mechanisms may allow ILDs to be computed for complex stimuli with rapid spectrotemporally-modulated envelopes such as speech and animal vocalizations and moving sound sources.http://journal.frontiersin.org/Journal/10.3389/fncir.2014.00144/fullSound Localizationcalyx of heldtemporal processinginteraural level differencelateral superior olivemedial nucleus of the trapezoid body |
| spellingShingle | Daniel J Tollin Kanthaiah eKoka Linear coding of complex sound spectra by discharge rate by neurons of the medial nucleus of the trapezoidal body (MNTB) and thier inputs Frontiers in Neural Circuits Sound Localization calyx of held temporal processing interaural level difference lateral superior olive medial nucleus of the trapezoid body |
| title | Linear coding of complex sound spectra by discharge rate by neurons of the medial nucleus of the trapezoidal body (MNTB) and thier inputs |
| title_full | Linear coding of complex sound spectra by discharge rate by neurons of the medial nucleus of the trapezoidal body (MNTB) and thier inputs |
| title_fullStr | Linear coding of complex sound spectra by discharge rate by neurons of the medial nucleus of the trapezoidal body (MNTB) and thier inputs |
| title_full_unstemmed | Linear coding of complex sound spectra by discharge rate by neurons of the medial nucleus of the trapezoidal body (MNTB) and thier inputs |
| title_short | Linear coding of complex sound spectra by discharge rate by neurons of the medial nucleus of the trapezoidal body (MNTB) and thier inputs |
| title_sort | linear coding of complex sound spectra by discharge rate by neurons of the medial nucleus of the trapezoidal body mntb and thier inputs |
| topic | Sound Localization calyx of held temporal processing interaural level difference lateral superior olive medial nucleus of the trapezoid body |
| url | http://journal.frontiersin.org/Journal/10.3389/fncir.2014.00144/full |
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