|A personal message from Dr Mark Hill (May 2020)
| I have decided to take early retirement in September 2020. During the many years online I have received wonderful feedback from many readers, researchers and students interested in human embryology. I especially thank my research collaborators and contributors to the site. The good news is Embryology will remain online and I will continue my association with UNSW Australia. I look forward to updating and including the many exciting new discoveries in Embryology!
Central auditory neural pathway
This diagram gives an overview of the central neural pathway from the cochlea through the brainstem nuclei to the auditory cortex. Note that this neural pathway can be analysed postnatally by Automated Auditory Brainstem Response.
- auditory nerve (cochlear nerve, acoustic nerve) part of the vestibulocochlear nerve (8th cranial nerve, CN VIII)
- cochlear nuclei (dorsal cochlear nucleus, ventral cochlear nucleus)
- superior olivary complex (SOC, superior olive)
- lateral lemniscus
- inferior colliculus
- medial geniculate nucleus
- auditory cortex
Some Recent Findings
- Effects of transient auditory deprivation during critical periods on the development of auditory temporal processing "The central auditory pathway matures through sensory experiences and it is known that sensory experiences during periods called critical periods exert an important influence on brain development. The present study aimed to investigate whether temporary auditory deprivation during critical periods could have a detrimental effect on the development of auditory temporal processing. MATERIALS AND METHODS: Twelve neonatal rats were randomly assigned to control and study groups; Study group experienced temporary (18-20 days) auditory deprivation during critical periods (Early deprivation study group). Outcome measures included changes in auditory brainstem response (ABR), gap prepulse inhibition of the acoustic startle reflex (GPIAS), and gap detection threshold (GDT). To further delineate the specific role of CPs in the outcome measures above, the same paradigm was applied in adult rats (Late deprivation group) and the findings were compared with those of the neonatal rats. RESULTS: Soon after the restoration of hearing, early deprivation study animals showed a significantly lower GPIAS at intermediate gap durations and a larger GDT than early deprivation controls, but these differences became insignificant after subsequent auditory inputs. Additionally, the ABR results showed significantly delayed latencies of waves IV, V, and interpeak latencies of wave I-III and wave I-V in study group. Late deprivation group didn't exhibit any deterioration in temporal processing following sensory deprivation. CONCLUSION: Taken together, the present results suggest that transient auditory deprivation during critical periods might cause reversible disruptions in the development of temporal processing." Rat Development
- Myelin development, plasticity, and pathology in the auditory system "Myelin allows for the rapid and precise timing of action potential propagation along neuronal circuits and is essential for healthy auditory system function. In this article, we discuss what is currently known about myelin in the auditory system with a focus on the timing of myelination during auditory system development, the role of myelin in supporting peripheral and central auditory circuit function, and how various myelin pathologies compromise auditory information processing. Additionally, in keeping with the increasing recognition that myelin is dynamic and is influenced by experience throughout life, we review the growing evidence that auditory sensory deprivation alters myelin along specific segments of the brain's auditory circuit." hearing test
- The precise temporal pattern of prehearing spontaneous activity is necessary for tonotopic map refinement "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....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."
- Formation and maturation of the calyx of Held "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. ... 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."
|More recent papers
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Search term: Hearing Neural Pathway Development
<pubmed limit=5>Hearing Neural Pathway Development</pubmed>
Mass of nerve cells is divided into three groups.
|A Geniculate ganglion (taste group, motor and sympathetic)
||B Spiral ganglion (cochlear group)
||C Vestibular ganglion (balance group)
Afferent (sensory) cranial nerve brainstem primary terminal nuclei
|Adult cochlea nerve glia diagram
- forms beside otocyst
- from wall of otocyst and neural crest cells
- bipolar neurons
- outer end of internal acoustic meatus
- innervate hair cells in membranous labyrinth
- axons project to brain stem and synapse in vestibular nucleus
- cell bodies lie in modiolus
- central pillar of cochlear
- innervate hair cells of spiral organ
- axons project to cochlear nucleus
|Cochlea glial lineage
||Adult cochlea nerve glia cartoon
Auditory Sound Localization Circuits in the Mammalian Brainstem
Schematic drawing of primary auditory sound localization circuits in the mammalian brainstem. For clarity, only the LSO or MSO are shown on each side.
Except for the auditory nerve, excitatory connections are shown in green and inhibitory connections are shown in red.
- AN - auditory nerve
- CN - cochlear nucleus
- HF - high frequency
- LF - low frequency
- Links: Hearing - Inner Ear Development
Calyx of Held
A specialised mammalian auditory brainstem synaptic structure. Ventral cochlear nucleus (VCN) globular bushy cells project to the contralateral, but not ipsilateral, medial nucleus of the trapezoid body (MNTB), where they form this specialised structure, named by Hans Held (1893). The VCN-MNTB pathway is required for calculating the interaural intensity and time differences.
- ↑ Kim BJ, Kim J, Park IY, Jung JY, Suh MW & Oh SH. (2018). Effects of transient auditory deprivation during critical periods on the development of auditory temporal processing. Int. J. Pediatr. Otorhinolaryngol. , 104, 66-71. PMID: 29287884 DOI.
- ↑ Long P, Wan G, Roberts MT & Corfas G. (2018). Myelin development, plasticity, and pathology in the auditory system. Dev Neurobiol , 78, 80-92. PMID: 28925106 DOI.
- ↑ Clause A, Kim G, Sonntag M, Weisz CJ, Vetter DE, Rűbsamen R & Kandler K. (2014). The precise temporal pattern of prehearing spontaneous activity is necessary for tonotopic map refinement. Neuron , 82, 822-35. PMID: 24853941 DOI.
- ↑ Roy PN, Mehra KS & Deshpande PJ. (1975). Cataract surgery performed before 800 B.C. Br J Ophthalmol , 59, 171. PMID: 1093567
- ↑ 5.0 5.1 5.2 Locher H, de Groot JC, van Iperen L, Huisman MA, Frijns JH & Chuva de Sousa Lopes SM. (2014). Distribution and development of peripheral glial cells in the human fetal cochlea. PLoS ONE , 9, e88066. PMID: 24498246 DOI.
- ↑ Kandler K, Clause A & Noh J. (2009). Tonotopic reorganization of developing auditory brainstem circuits. Nat. Neurosci. , 12, 711-7. PMID: 19471270 DOI.
- ↑ Nakamura PA & Cramer KS. (2011). Formation and maturation of the calyx of Held. Hear. Res. , 276, 70-8. PMID: 21093567 DOI.
- ↑ Held H. Die zentrale Gehörleitung. (The Central Auditory Pathway) Arch Anat Physiol Anat Abtheil. 1893;17:201–248.
Kandler K, Clause A & Noh J. (2009). Tonotopic reorganization of developing auditory brainstem circuits. Nat. Neurosci. , 12, 711-7. PMID: 19471270 DOI.
Search Pubmed: Hearing Neural Pathway
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Cite this page: Hill, M.A. (2020, July 16) Embryology Hearing - Neural Pathway. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Hearing_-_Neural_Pathway
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