Auditory cortex
Overview
The Auditory cortex is the part of the temporal lobe that processes auditory information in humans and many other vertebrates. It is a part of the auditory system, performing basic and higher functions in hearing, such as possible relations to language switching.
Anatomy
The auditory cortex is located within the Sylvian fissure, also known as the lateral sulcus, which separates the temporal lobe from the frontal and parietal lobes. It is part of the superior temporal gyrus, which also includes Wernicke's area—important for the processing of speech.
The auditory cortex is divided into three separate parts: the primary, secondary, and tertiary auditory cortices. Each of these areas has a distinct structure and function.
Primary Auditory Cortex
The primary auditory cortex (A1) is the first cortical destination of auditory information originating from the thalamus. It is located on the superior temporal gyrus and is responsible for the basic processing of sound, including pitch and volume.
Secondary Auditory Cortex
The secondary auditory cortex (A2) surrounds A1 and is involved in more complex processing of sound, including the interpretation of rhythm and melody.
Tertiary Auditory Cortex
The tertiary auditory cortex, also known as the auditory association area, is involved in the highest level of auditory processing. This area is responsible for the interpretation of complex sounds such as speech and music.
Function
The auditory cortex plays a crucial role in the perception of sound. It receives and processes auditory stimuli from the cochlea, the sensory organ of hearing located in the inner ear. The auditory cortex is responsible for a variety of auditory tasks, including the localization of sound in space, the identification of voices, and the understanding of speech.
Sound Localization
The auditory cortex is involved in determining the location of a sound source. This is achieved by processing the differences in time and intensity of sound signals received by the two ears.
Voice Identification
The auditory cortex is also involved in the identification of voices. This is a complex process that involves the integration of information about pitch, timbre, and rhythm.
Speech Understanding
The auditory cortex plays a crucial role in the understanding of speech. It is involved in the decoding of complex auditory signals into meaningful linguistic units such as words and sentences.
Clinical Significance
Damage to the auditory cortex can result in a variety of auditory deficits, including difficulty in recognizing speech and music, and in localizing sound sources. These deficits are collectively referred to as auditory agnosia.
In addition, the auditory cortex is a target of investigation in the development of cochlear implants, devices that can restore some level of hearing to individuals with severe to profound hearing loss.