The medial superior olivary nucleus contains neurons with both medial and lateral dendrites. The synapses on the medial dendrites are mostly excitatory and come from the contralateral ventral cochlear nucleus. On the other hand, the synapses on the lateral dendrites are primarily inhibitory and originate from the ipsilateral ventral cochlear nucleus. The differences in the phase of the sound that reaches the two ears affect the strength and timing of the excitation and inhibition that reach a specific medial superior olivary neuron. The lateral superior olivary nucleus is responsible for processing differences in the sound intensity that reaches the two ears, providing information about the source of the sound. The activity of superior olivary neurons can offer insights into sound localization.

The primary auditory cortex shares several features with other primary sensory areas. It not only contains sensory maps, specifically tonotopic maps, but it also performs feature extraction. Neurons in the primary auditory cortex form isofrequency columns, where neurons within a column have the same characteristic frequency. Additionally, they form alternating columns known as summation and suppression columns. Neurons in summation columns are more responsive to binaural input compared to monaural input. On the other hand, neurons in suppression columns are less responsive to binaural stimulation, and the response to one ear dominates. Some neurons are selective for the direction of frequency change.

Bilateral lesions of the auditory cortex have some impact on the ability to distinguish the frequency or intensity of different sounds. They also reduce the abilities to localize sound and understand speech. However, unilateral lesions have minimal effects, particularly if they occur in the nondominant hemisphere for language. Evidently, frequency discrimination relies on activity at lower levels of the auditory pathway, potentially involving the inferior colliculus.

In clinical settings, two simple tests are often used to differentiate the most important types of deafness: conduction loss and sensorineural loss. Conduction hearing loss occurs in disorders of the external ear, such as a blocked ear canal due to cerumen, or in the middle ear, for example, a ruptured eardrum. Sensorineural hearing loss reflects disorders in the inner ear, the cochlear nerve, or central connections.

The Weber test is utilized to assess the magnitude of conduction hearing loss. In this test, the base of a vibrating tuning fork is placed against the middle of the person's forehead, and the person is asked to localize the sound. Normally, the sound is not localized to a specific ear. However, if the person has conductive hearing loss, such as due to a punctured tympanic membrane, fluid in the middle ear, otosclerosis, or a loss of continuity in the ossicular chain, the sound is localized to the deaf ear because it is conducted to the cochlea through bone. Although the sound is also conducted to the cochlea of the undamaged ear, bone-conducted sound does not activate the organ of Corti as effectively as sound conducted normally through the tympanic membrane and ossicle chain. One possible reason why the sound in the Weber test is not localized to the normal ear may be that the hearing in the normal ear is inhibited by the ambient sound level, known as auditory masking. Conversely, in people with sensorineural hearing loss, caused by damage to the organ of Corti, the cochlear nerve, or the cochlear nuclei, the sound is localized to the normal side.
For example, neurons in the medial superior olivary nucleus have medial and lateral dendrites. The synapses on the medial dendrites are largely excitatory, and they originate from the contralateral ventral cochlear nucleus. Those on the lateral dendrites are mostly inhibitory and come from the ipsilateral ventral cochlear nucleus. Differences in the phase of the sound reaching the two ears affect the strength and timing of the excitation and inhibition reaching a particular medial superior olivary neuron. The lateral superior olivary nucleus processes differences in the sound intensity that reaches the two ears to provide information about the source of the sound. The activity of superior olivary neurons can provide information about sound localization.
Several features of the primary auditory cortex resemble those of other primary sensory areas. Not only are sensory maps—in this case, tonotopic maps—present in the auditory cortex but also this cortical region performs feature extraction. Neurons in the primary auditory cortex form isofrequency columns (in which the neurons in the column have the same characteristic frequency), and they also form alternating columns, known as summation and suppression columns. Neurons in summation columns are more responsive to binaural than to monaural input. Neurons in suppression columns are less responsive to binaural than to monaural stimulation, and, accordingly, the response to one ear is dominant. Some neurons are selective for the direction of frequency change.
Bilateral lesions of the auditory cortex have some effect on the ability to distinguish the frequency or intensity of different sounds, and they reduce the abilities to localize sound and to understand speech. Unilateral lesions, however, have little effect, especially if the nondominant (for language) hemisphere is involved (see ). Evidently, frequency discrimination depends on activity at lower levels of the auditory pathway, possibly the inferior colliculus.
Twosimpletestsareoftenusedclinicallytodistinguishthemostimportanttypesofdeafness:conduction loss andsensorineural loss. Conductionhearinglossoccursindisordersoftheexternalear(e.g.,earcanalblockedbycerumen)ormiddleear(e.g.,ruptureoftheeardrum).Sensorineuralhearinglossreflectsdisordersoftheinnerear,thecochlearnerve,orcentralconnections.
TheWeber test isusedtoevaluatethemagnitudeofconductionhearingloss.Inthistest,thebaseofavibratingtuningforkisplacedagainstthemiddleoftheperson’sforehead,andthepersonisaskedtolocalizethesound.Normally,thesoundisnotlocalizedtoaparticularear.However,ifthepersonhasconductivehearingloss(e.g.,duetoapuncturedtympanicmembrane,fluidinthemiddleear,otosclerosis,orlossofcontinuityoftheossicularchain),thesoundislocalizedtothedeafearbecauseitisconductedtothecochleathroughbone.Thesoundisalsoconductedtothecochleaoftheundamagedear,butbone-conductedsounddoesnotactivatetheorganofCortiaswellasdoessoundconductednormallythroughthetympanicmembraneandossiclechain.OnereasonwhythesoundintheWebertestisnotlocalizedtothenormalearmaybethathearinginthenormalearisinhibitedbytheambientsoundlevel(auditory masking). Conversely,inpeoplewithsensorineuralhearingloss(e.g.,duetodamagetotheorganofCorti,thecochlearnerve,orthecochlearnuclei),thesoundislocalizedtothenormalside.