Talk:Hearing - Neural Pathway
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Cite this page: Hill, M.A. (2024, April 23) Embryology Hearing - Neural Pathway. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Talk:Hearing_-_Neural_Pathway |
2014
The precise temporal pattern of prehearing spontaneous activity is necessary for tonotopic map refinement
Neuron. 2014 May 21;82(4):822-35. doi: 10.1016/j.neuron.2014.04.001.
Clause A1, Kim G2, Sonntag M3, Weisz CJ4, Vetter DE5, Rűbsamen R3, Kandler K6.
Abstract
Patterned spontaneous activity is a hallmark of developing sensory systems. In the auditory system, rhythmic bursts of spontaneous activity are generated in cochlear hair cells and propagated along central auditory pathways. The role of these activity patterns in the development of central auditory circuits has remained speculative. Here we demonstrate that blocking efferent cholinergic neurotransmission to developing hair cells in mice that lack the α9 subunit of nicotinic acetylcholine receptors (α9 KO mice) altered the temporal fine structure of spontaneous activity without changing activity levels. KO mice showed a severe impairment in the functional and structural sharpening of an inhibitory tonotopic map, as evidenced by deficits in synaptic strengthening and silencing of connections and an absence in axonal pruning. These results provide evidence that the precise temporal pattern of spontaneous activity before hearing onset is crucial for the establishment of precise tonotopy, the major organizing principle of central auditory pathways. Copyright © 2014 Elsevier Inc. All rights reserved.
PMID 24853941
2011
Formation and maturation of the calyx of Held
Hear Res. 2011 Jun;276(1-2):70-8. doi: 10.1016/j.heares.2010.11.004. Epub 2010 Nov 18.
Nakamura PA1, Cramer KS.
Abstract
Sound localization requires precise and specialized neural circuitry. A prominent and well-studied specialization is found in the mammalian auditory brainstem. Globular bushy cells of the ventral cochlear nucleus (VCN) project contralaterally to neurons of the medial nucleus of the trapezoid body (MNTB), where their large axons terminate on cell bodies of MNTB principal neurons, forming the calyces of Held. The VCN-MNTB pathway is necessary for the accurate computation of interaural intensity and time differences; MNTB neurons provide inhibitory input to the lateral superior olive, which compares levels of excitation from the ipsilateral ear to levels of tonotopically matched inhibition from the contralateral ear, and to the medial superior olive, where precise inhibition from MNTB neurons tunes the delays of binaural excitation. Here we review the morphological and physiological aspects of the development of the VCN-MNTB pathway and its calyceal termination, along with potential mechanisms that give rise to its precision. During embryonic development, VCN axons grow towards the midline, cross the midline into the region of the presumptive MNTB and then form collateral branches that will terminate in calyces of Held. In rodents, immature calyces of Held appear in MNTB during the first few days of postnatal life. These calyces mature morphologically and physiologically over the next three postnatal weeks, enabling fast, high fidelity transmission in the VCN-MNTB pathway. Copyright © 2010 Elsevier B.V. All rights reserved.
PMID 21093567
2009
Tonotopic reorganization of developing auditory brainstem circuits
Nat Neurosci. 2009 Jun;12(6):711-7. doi: 10.1038/nn.2332. Epub 2009 May 10.
Kandler K1, Clause A, Noh J.
Abstract
A fundamental organizing principle of auditory brain circuits is tonotopy, the orderly representation of the sound frequency to which neurons are most sensitive. Tonotopy arises from the coding of frequency along the cochlea and the topographic organization of auditory pathways. The mechanisms that underlie the establishment of tonotopy are poorly understood. In auditory brainstem pathways, topographic precision is present at very early stages in development, which may suggest that synaptic reorganization contributes little to the construction of precise tonotopic maps. Accumulating evidence from several brainstem nuclei, however, is now changing this view by demonstrating that developing auditory brainstem circuits undergo a marked degree of refinement on both a subcellular and circuit level. PMID 19471270
