Auditory cortex



The primary auditory cortex is the region of the brain that is responsible for processing of auditory (sound) information.

Function of primary auditory cortex
As with other primary sensory cortical areas, auditory sensations reach perception only if received and processed by a cortical area.

Neurons in the auditory cortex are organised according to the frequency of sound to which they respond best. Neurons at one end of the auditory cortex respond best to low frequencies; neurons at the other respond best to high frequencies. There are multiple auditory areas (much like the multiple areas in the visual cortex), which can be distinguished anatomically and on the basis that they contain a complete "frequency map." The purpose of this frequency map (known as a tonotopic map) is unknown and is likely to reflect the fact that the sensory epithelium of the auditory system, the cochlea, is arranged according to sound frequency. The auditory cortex is involved in tasks such as identifying and segregating auditory "objects" and identifying the location of a sound in space.

Human brain scans have indicated that a peripheral bit of this brain region is active when trying to identify pitch. Individual cells consistently get excited by sounds at specific frequencies, or multiples of that frequency.

The primary auditory cortex is about the same as Brodmann areas 41 and 42. It lies in the posterior half of the superior temporal gyrus and also dives into the lateral sulcus as the transverse temporal gyri (also called Heschl's gyri).

Brodmann area 41
This area is also known as anterior transverse temporal area 41 (H). It is a subdivision of the cytoarchitecturally-defined temporal region of cerebral cortex, occupying the anterior transverse temporal gyrus (H) in the bank of the lateral sulcus on the dorsal surface of the temporal lobe. Brodmann area 41 is bounded medially by the parainsular area 52 (H) and laterally by the posterior transverse temporal area 42 (H) (Brodmann-1909).

Brodmann area 42
This area is also known as posterior transverse temporal area 42 (H). It is a subdivision of the cytoarchitecturally-defined temporal region of cerebral cortex, located in the bank of the lateral sulcus on the dorsal surface of the temporal lobe. Brodmann area 42 is bounded medially by the anterior transverse temporal area 41 (H) and laterally by the superior temporal area 22 (Brodmann-1909).