Auditory pathways of the brain

Auditory pathways of the Auditory pathways of the BrainBrain

Once sound information has Once sound information has been received by the auditory been received by the auditory (VIIIth) nerve, there can be no (VIIIth) nerve, there can be no further information added to the further information added to the stimulus.stimulus.


•Cochlear Nucleus Cochlear Nucleus

Each earEach ear has a cochlea and an has a cochlea and an auditory VIIIth nerve which auditory VIIIth nerve which transfers the sound from the transfers the sound from the cochlea to the cochlea to the Cochlear NucleusCochlear Nucleus..


•Cochlear NucleusCochlear Nucleus

It is located at the junction of It is located at the junction of the Pons and Medulla in the the Pons and Medulla in the brainstem.brainstem.


• Cochlear NucleusCochlear Nucleus

Two thirds of the auditory Two thirds of the auditory information received moves information received moves through the trapezoid body of the through the trapezoid body of the brainstem into the brainstem into the superior olivary superior olivary complexcomplex of the opposite of the opposite hemisphere of the brain.hemisphere of the brain.


•Superior Olivary ComplexSuperior Olivary Complex

They are located in the They are located in the MedullaMedulla area of the brain. (each ear has area of the brain. (each ear has one)one)


• BrainstemBrainstem

The brainstem consists of three The brainstem consists of three structures. They are:structures. They are:

1.1. The MedullaThe Medulla

2.2. The PonsThe Pons

3.3. The MidbrainThe Midbrain


•Nucleus of Lateral LemniscusNucleus of Lateral Lemniscus

They are located in the They are located in the PonsPons region of the brainstem.region of the brainstem.


• Inferior colliculusInferior colliculus

They are located in the They are located in the midbrainmidbrain area of the brainstemarea of the brainstem


• ThalmusThalmus

It is the major distribution center It is the major distribution center for sensory activity of the brain.for sensory activity of the brain.

It is located in the It is located in the diencephalondiencephalon which lies superior to the which lies superior to the midbrain.midbrain.


•ThalmusThalmus

This is where the This is where the medial medial geniculate bodygeniculate body is located. From is located. From this body, the neural pathway this body, the neural pathway “fans out” toward the “fans out” toward the auditory auditory cortexcortex of each temporal lobe. of each temporal lobe.


The neural pathways divide into The neural pathways divide into two described paths. They are:two described paths. They are:

1.1. The ipsilateral path (same side)The ipsilateral path (same side)

2.2. The contralateral path (opposite The contralateral path (opposite side)side)


Please refer to the hierarchy Please refer to the hierarchy travel diagram of the auditory travel diagram of the auditory neural pathway as described on neural pathway as described on page #95 of Lass & Woodford.page #95 of Lass & Woodford.

Please keep in mind, this Please keep in mind, this pathway is for pathway is for each eareach ear..


• Auditory brain reception areasAuditory brain reception areas

There are two behavioral areas There are two behavioral areas where sound information is where sound information is processed. They are:processed. They are:

1.1. The brainstemThe brainstem

2.2. The auditory cortexThe auditory cortex


•Brainstem ProcessingBrainstem Processing

This behavioral auditory This behavioral auditory reception area is where lower reception area is where lower level processing such as the level processing such as the perception of loudness and pitch perception of loudness and pitch occur.occur.


•Auditory Cortex ProcessingAuditory Cortex Processing

This is where high level auditory This is where high level auditory processing behavior occurs such processing behavior occurs such as the understanding of speech, as the understanding of speech, speech in noise, and other speech in noise, and other complex signals.complex signals.


Please refer to Lass & Woodford Please refer to Lass & Woodford page #96 for some nice page #96 for some nice “landmark” definition of the “landmark” definition of the brain anatomy.brain anatomy.

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Auditory pathways of the brain