Article

Parallel auditory pathways: Projection patterns of the different neuronal populations in the dorsal and ventral cochlear nuclei

Department of Neurobiology, Duke University Medical Center, P.O. Box 3209, Durham, NC 27710, USA.
Brain Research Bulletin (Impact Factor: 2.72). 07/2003; 60(5-6):457-74. DOI: 10.1016/S0361-9230(03)00050-9
Source: PubMed

ABSTRACT

The cochlear nuclear complex gives rise to widespread projections to nuclei throughout the brainstem. The projections arise from separate, well-defined populations of cells. None of the cell populations in the cochlear nucleus projects to all brainstem targets, and none of the targets receives inputs from all cell types. The projections of nine distinguishable cell types in the cochlear nucleus-seven in the ventral cochlear nucleus and two in the dorsal cochlear nucleus-are described in this review. Globular bushy cells and two types of spherical bushy cells project to nuclei in the superior olivary complex that play roles in sound localization based on binaural cues. Octopus cells convey precisely timed information to nuclei in the superior olivary complex and lateral lemniscus that, in turn, send inhibitory input to the inferior colliculus. Cochlear root neurons send widespread projections to areas of the reticular formation involved in startle reflexes and autonomic functions. Type I multipolar cells may encode complex features of natural stimuli and send excitatory projections directly to the inferior colliculus. Type II multipolar cells send inhibitory projections to the contralateral cochlear nuclei. Fusiform cells in the dorsal cochlear nucleus appear to be important for the localization of sounds based on spectral cues and send direct excitatory projections to the inferior colliculus. Giant cells in the dorsal cochlear nucleus also project directly to the inferior colliculus; some of them may convey inhibitory inputs to the contralateral cochlear nucleus as well.

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    • "That the timing of S1 responses is driven primarily by the PC input exploits the highly informative nature of the PC timing signal. Separate sensory channels that convey complementary but overlapping information are commonplace in sensory systems and not limited to the sense of touch; the visual (Field and Chichilnisky, 2007), auditory (Cant and Benson, 2003), gustatory (Zhang et al., 2003), olfactory (Uchida et al., 2014), and vestibular (Goldberg, 2000; Sadeghi et al., 2007) systems all involve many types of afferents. Distributing sensory information across channels has distinct advantages such as parsing the behaviorally relevant range (Dominy and Lucas, 2001), keeping energy expenditure low (Gjorgjieva et al., 2014), and optimizing information transmission in the presence of noise (Kastner et al., 2015 ). "
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    • "The CNC distributes the incoming auditory information to distinct ascending pathways in the brainstem (Fig. 3). Major projections of the DCN innervate the contralateral nuclei of the LL and the IC (Cant and Benson 2003). The VCN projects mainly into the region of the ipsilateral and contralateral SOC. "
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    • "The IC is also the initial converging center of the central auditory system (Casseday et al., 2002; Ehret, 1997). Once the sound information is transmitted from the auditory nerve to the brain, it gets processed across multiple structures within the brainstem through several diverging pathways (Cant and Benson, 2003). The ascending sound information and pathways then converge, for the most part, into the ICC en route to the thalamus and cortex. "
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