Projections from the anteroventral cochlear nucleus to the lateral and medial superior olivary nuclei

Cant, Nell B.; Casseday, John H.

doi:10.1002/cne.902470406

Cited by 273 publications

(173 citation statements)

References 29 publications

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“…The first stage is a phenomenological model of ANFs that produces realistic temporal discharge patterns to both acoustic pure tones and electric pulse trains (Nourski et al 2006). MSO neurons receive bilateral excitatory inputs from ANFs via spherical bushy cells (SBCs) in the VCN, as well as bilateral inhibitory inputs originating from globular bushy cells in the VCN (Cant and Casseday 1986;Smith et al 1993). In our implementation, the SBC stage was omitted because SBC shows little coincidence detection themselves (Wang and Delgutte 2012).…”

Section: Methodsmentioning

confidence: 99%

Modeling Binaural Responses in the Auditory Brainstem to Electric Stimulation of the Auditory Nerve

Chung

Delgutte

Colburn

2014

JARO

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Bilateral cochlear implants (CIs) provide improvements in sound localization and speech perception in noise over unilateral CIs. However, the benefits arise mainly from the perception of interaural level differences, while bilateral CI listeners' sensitivity to interaural time difference (ITD) is poorer than normal. To help understand this limitation, a set of ITD-sensitive neural models was developed to study binaural responses to electric stimulation. Our working hypothesis was that central auditory processing is normal with bilateral CIs so that the abnormality in the response to electric stimulation at the level of the auditory nerve fibers (ANFs) is the source of the limited ITD sensitivity. A descriptive model of ANF response to both acoustic and electric stimulation was implemented and used to drive a simplified biophysical model of neurons in the medial superior olive (MSO). The model's ITD sensitivity was found to depend strongly on the specific configurations of membrane and synaptic parameters for different stimulation rates. Specifically, stronger excitatory synaptic inputs and faster membrane responses were required for the model neurons to be ITD-sensitive at high stimulation rates, whereas weaker excitatory synaptic input and slower membrane responses were necessary at low stimulation rates, for both electric and acoustic stimulation. This finding raises the possibility of frequency-dependent differences in neural mechanisms of binaural processing; limitations in ITD sensitivity with bilateral CIs may be due to a mismatch between stimulation rate and cell parameters in ITD-sensitive neurons.

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Section: Methodsmentioning

confidence: 99%

Modeling Binaural Responses in the Auditory Brainstem to Electric Stimulation of the Auditory Nerve

Chung

Delgutte

Colburn

2014

JARO

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“…It is comprised of diverse and highly specialised neuronal populations (Ram on y Cajal c.1900;Lorente de N o, 1933Lorente de N o, , 1981 differing in morphology (Harrison and Warr, 1962;Osen, 1969a;and 1969b;Brawer et al, 1974;Heiman-Patterson and Strominger, 1985;Adams, 1986), response properties (Pfeiffer and Kiang, 1965;Pfeiffer, 1966;Evans and Nelson, 1973;Shofner and Young, 1985;Blackburn and Sachs, 1989;Winter and Palmer, 1990;Marsh et al, 2006), and connectivity with the auditory nerve (Liberman, 1991(Liberman, , 1993. Each neuronal population in the CN exhibits distinct projections (summarised in Cant and Benson, 2003), some ipsilateral (Cant and Casseday, 1986), others contralateral (Warr, 1966(Warr, , 1969Winer and Schreiner, 2005), reflecting the distinct functions of the CN anteroventral (involved in sound localisation) and posteroventral regions (involved in sound discrimination) (Eggermont, 2001).…”

Section: Cochlear Nucleusmentioning

confidence: 99%

Subcortical processing in auditory communication

2015

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a b s t r a c tThe voice is a rich source of information, which the human brain has evolved to decode and interpret. Empirical observations have shown that the human auditory system is especially sensitive to the human voice, and that activity within the voice-sensitive regions of the primary and secondary auditory cortex is modulated by the emotional quality of the vocal signal, and may therefore subserve, with frontal regions, the cognitive ability to correctly identify the speaker's affective state. So far, the network involved in the processing of vocal affect has been mainly characterised at the cortical level. However, anatomical and functional evidence suggests that acoustic information relevant to the affective quality of the auditory signal might be processed prior to the auditory cortex.Here we review the animal and human literature on the main subcortical structures along the auditory pathway, and propose a model whereby the distinction between different types of vocal affect in auditory communication begins at very early stages of auditory processing, and relies on the analysis of individual acoustic features of the sound signal. We further suggest that this early feature-based decoding occurs at a subcortical level along the ascending auditory pathway, and provides a preliminary coarse (but fast) characterisation of the affective quality of the auditory signal before the more refined (but slower) cortical processing is completed.

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“…Type V units are binaurally excited (EE) and exhibit the "peak" binaural delay that is typically observed in the medial superior olive (MSO) Ramachandran and May 2002). Because spherical bushy cells (SBCs) in the anterior subdivision of the VCN project bilaterally to the MSO (Cant and Casseday 1986;Smith et al 1993), the dominant ascending inputs of type V units originate in the VCN.…”

Section: Type X and Tail Unitsmentioning

confidence: 99%

“…Median SR is based only on spontaneously active units with BFs within two octaves of the EDGE suggest that their binaural responses are dictated by inputs from the lateral superior olive (LSO) (Ramachandran and May 2002). The LSO receives excitatory inputs from SBCs in the ipsilateral VCN (Cant and Casseday 1986;Cant and Benson 2003). Inhibitory inputs originate in the ipsilateral medial nucleus of the trapezoid body (MNTB) which are driven by globular bushy cells (GBCs) in the contralateral VCN (Kuwabara et al 1991;Smith et al 1991).…”

Section: Type X and Tail Unitsmentioning

confidence: 99%

Effects of Unilateral Acoustic Trauma on Tinnitus-Related Spontaneous Activity in the Inferior Colliculus

Ropp

Tiedemann

Young

et al. 2014

JARO

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This study describes the long-term effects of soundinduced cochlear trauma on spontaneous discharge rates in the central nucleus of the inferior colliculus (ICC). As in previous studies, single-unit recordings in Sprague-Dawley rats revealed pervasive increases in spontaneous discharge rates. Based on differences in their sources of input, it was hypothesized that physiologically defined neural populations of the auditory midbrain would reveal the brainstem sources that dictate ICC hyperactivity. Abnormal spontaneous activity was restricted to target neurons of the ventral cochlear nucleus. Nearly identical patterns of hyperactivity were observed in the contralateral and ipsilateral ICC. The elevation in spontaneous activity extended to frequencies well below and above the region of maximum threshold shift. This lack of frequency organization suggests that ICC hyperactivity may be influenced by regions of the brainstem that are not tonotopically organized. Sound-induced hyperactivity is often observed in animals with behavioral signs of tinnitus. Prior to electrophysiological recording, rats were screened for tinnitus by measuring gap pre-pulse inhibition of the acoustic startle reflex (GPIASR). Rats with positive phenotypes did not exhibit unique patterns of ICC hyperactivity. This ambiguity raises concerns regarding animal behavioral models of tinnitus. If our screening procedures were valid, ICC hyperactivity is observed in animals without behavioral indications of the disorder. Alternatively, if the perception of tinnitus is strictly linked to ongoing ICC hyperactivity, our current behavioral approach failed to provide a reliable assessment of tinnitus state.

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Projections from the anteroventral cochlear nucleus to the lateral and medial superior olivary nuclei

Cited by 273 publications

References 29 publications

Modeling Binaural Responses in the Auditory Brainstem to Electric Stimulation of the Auditory Nerve

Modeling Binaural Responses in the Auditory Brainstem to Electric Stimulation of the Auditory Nerve

Subcortical processing in auditory communication

Effects of Unilateral Acoustic Trauma on Tinnitus-Related Spontaneous Activity in the Inferior Colliculus

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