Auditory Pathway

Definition

The auditory neural pathway in the central nervous system transmits and processes sound signals from the ear to the cortex. The configuration of the pathway is multisynaptic and bilaterally projecting.

Current Knowledge

From the Outer Ear to the Cochlear Nuclei

Sound is transmitted as longitudinal waves through the air, enters the outer ear, and vibrates the tympanic membrane. The three “tiny bones” of the middle ear, the ossicles (malleus, incus, and stapes), amplify and transmit these vibrations to the oval window, producing waves in the scala vestibuli, a fluid-filled compartment within the coil-shaped cochlea of the inner ear. These fluid waves distort the stiff basilar membrane. Residing on this membrane, hair cells within the organ of Corti transduce the minute movements of the membrane into the graded release of glutamate onto the peripheral processes of bipolar afferent fibers, whose cell bodies are located in the spiral ganglion. The central processes exit the base...