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Commissural axons of the mouse cochlear nucleus
M Christian Brown1, Marie Drottar, Thane E Benson
1Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts 02114, USA. chris_brown@meei.harvard.edu
The Journal of Comparative Neurology
|November 6, 2012
Summary
Commissural neurons in the cochlear nucleus project axons to the opposite ear. These radiate commissural axons are primarily inhibitory, potentially balancing auditory input between ears.
Area of Science:
- Neuroscience
- Auditory System Research
- Cochlear Nucleus Anatomy
Background:
- Commissural neurons connect the left and right cochlear nuclei.
- The origin and projection patterns of these neurons are not fully understood.
Purpose of the Study:
- To identify the origin of commissural axons projecting between cochlear nuclei.
- To characterize the morphology, termination patterns, and synaptic nature of these axons.
Main Methods:
- Anterograde tracer injections into the dorsal cochlear nucleus.
- Correlation of labeled axons with neuron populations.
- Axon reconstruction and electron microscopy.
Main Results:
- Radiate multipolar neurons are the predominant source of commissural axons.
- These axons are thick, myelinated, and cross the brainstem dorsally.
- Terminations are primarily within the cochlear nucleus core, forming symmetric (inhibitory) synapses.
Conclusions:
- Radiate commissural axons likely mediate broadband inhibition for contralateral sound.
- These axons may rapidly balance auditory input from both ears.
Related Concept Videos
01:13The Cochlea
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01:15Auditory Pathway
Auditory pathways constitute the complex neural circuits responsible for transmitting and interpreting auditory information from the peripheral auditory system to the brain. Sound waves are initially captured by the outer ear, funneled through the ear canal, and reach the tympanic membrane (eardrum). These vibrations are transmitted via the middle ear's ossicles to the inner ear's cochlea.
When viewed cross-sectionally, the cochlea reveals the scala vestibuli and scala tympani flanking the...
When viewed cross-sectionally, the cochlea reveals the scala vestibuli and scala tympani flanking the...
01:22Hair Cells
Hair cells are the sensory receptors of the auditory system—they transduce mechanical sound waves into electrical energy that the nervous system can understand. Hair cells are located in the organ of Corti within the cochlea of the inner ear, between the basilar and tectorial membranes. The actual sensory receptors are called inner hair cells. The outer hair cells serve other functions, such as sound amplification in the cochlea, and are not discussed in detail here.
01:16Anatomy of the Ear
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