Tonotopic Organization

Tonotopic Organization is the better coding and separation of the sound in certain parts of the organs in the auditory pathway according to its frequency.

Tonotopic Organization in the Cochlea:
The high frequency signals from the first parts of the cochlea reach the posterior part of the auditory cortex (posterior), and the low frequency signals from the last parts (heliotrema) reach the anterior part of the auditory cortex. Thus, the auditory cortex perceives the frequency analysis of the sound intact.
High frequencies = Treble sounds =The basal part of the cochlea
Low frequencies = Pes sounds = Apex part of the cochlea

Tonotopic Organization in Central Hearing System
• The nerve fibers from the spiral ganglion to the cochlear nucleus have tonotopic oprganization.
• In cochlear nuclei, tonotopic organization, low-frequency sounds and stimulation in the ventral nucleus, and high-frequency sounds in the dorsal nucleus.
• Medial Superior Oliver Core responds to low frequency inputs, while Lateral Superior Oliver Core responds to high frequency inputs.

Low frequencies = Pes sounds = Medial superior olive
High frequencies = Treble sounds = Lateral superior olive

Tonotopic organization in cochlear nuclei

In the cochlear nuclei, the tonotopic organization is encoded in the ventral nucleus, while low frequencies are encoded, while the high frequencies are coded in the dorsal nucleus.

Tonotopic Organization in Hearing Cortex

The auditory cortex has a cortical map in which data from the cochlea is tonotopically represented. Accordingly, the high frequency signals from the first parts of the cochlea reach the lower posterior part of the auditory cortex (posterior), and the low frequency signals from the heliotrope reach the anterior part of the auditory cortex. Thus, the auditory cortex perceives the frequency analysis of the sound intact. 8. If we look at the tonotopic organization in the cranial nerve; low frequency fibers pass through the inner part of the nerve, and high frequency fibers pass through the outer part of the nerve.

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