The Human Brain : From Neurone to Nervous System
AUDITORY PATHWAYS and SPEECH
- The Primary Auditory Cortex is the receiving area for signals from the ear. It is located in the middle third of the superior temporal gyrus (Brodmann's areas 41 and 42).
These areas are responsible for analysing the pitch and volume of sounds, as well as their location in space.
There is a map of the cochlea in the auditory cortex, in which there are frequency-specific neurones. This is described as a tonotopic map within which frequencies of sound are processed in different areas of the auditory cortex.
Unlike the somatosensory cortex, the each auditory cortex receives inputs from both cochleas, and the auditory pathway is bilateral from the medulla to the auditory cortex. This allows the time of arrival of sound at the two ears to be compared, starting in the medulla, and this information is used to located sounds.
Destruction of one auditory cortex results in slight hearing loss, but destruction of both areas results in cortical deafness.