Brodmann area 22 is a Brodmann's area that is cytoarchitecturally located in the posterior superior temporal gyrus of the

brain A brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It is located in the head, usually close to the sensory organs for senses such as vision. It is the most complex organ in a v ...

. In the left

cerebral hemisphere The vertebrate cerebrum (brain) is formed by two cerebral hemispheres that are separated by a groove, the longitudinal fissure. The brain can thus be described as being divided into left and right cerebral hemispheres. Each of these hemispheres ...

, it is one portion of

Wernicke's area Wernicke's area (; ), also called Wernicke's speech area, is one of the two parts of the cerebral cortex that are linked to speech, the other being Broca's area. It is involved in the comprehension of written and spoken language, in contrast to B ...

. The left hemisphere BA22 helps with generation and understanding of individual words. On the right side of the brain, BA22 helps to discriminate pitch and sound intensity, both of which are necessary to perceive

melody A melody (from Greek language, Greek μελῳδία, ''melōidía'', "singing, chanting"), also tune, voice or line, is a Linearity#Music, linear succession of musical tones that the listener perceives as a single entity. In its most liter ...

and prosody. Wernicke's area is active in processing language and consists of the left Brodmann area 22 and

Brodmann area 40 Brodmann area 40 (BA40) is part of the parietal cortex in the human brain. The inferior part of BA40 is in the area of the supramarginal gyrus, which lies at the posterior end of the lateral fissure, in the inferior lateral part of the parieta ...

, the

supramarginal gyrus The supramarginal gyrus is a portion of the parietal lobe. This area of the brain is also known as Brodmann area 40 based on the brain map created by Korbinian Brodmann to define the structures in the cerebral cortex. It is probably involved wit ...

. It is bounded rostrally by Brodmann area 38, medially by Brodmann area 42, ventrocaudally by Brodmann area 21, and dorsocaudally by

, and

Brodmann area 39 Brodmann area 39, or BA39, is part of the parietal cortex in the human brain. BA39 encompasses the angular gyrus, lying near to the junction of temporal, occipital and parietal lobes. This area is also known as angular area 39 (H). It corr ...

. These cortical regions surround the lower left posterior

Sylvian fissure In neuroanatomy, the lateral sulcus (also called Sylvian fissure, after Franciscus Sylvius, or lateral fissure) is one of the most prominent features of the human brain. The lateral sulcus is a deep fissure in each hemisphere that separates th ...

Language

The Brodmann areas that are relevant to language include Broca's area (BA 44/45) and Wernicke's area (BA 42/22), where Broca's area is responsible for language production and Wernicke's area is responsible for language comprehension.

Function

Brodmann area 22 (BA 22) combined with Brodmann area 42 (BA 42) form Wernicke’s area in the superior temporal gyrus in the

temporal lobe The temporal lobe is one of the four Lobes of the brain, major lobes of the cerebral cortex in the brain of mammals. The temporal lobe is located beneath the lateral fissure on both cerebral hemispheres of the mammalian brain. The temporal lobe ...

. Using cytoarchitectonics, BA 22 is located in the superior temporal gyrus which separates it from the primary and secondary auditory cortex. BA 22 is connected with nonverbal sound processing in the right hemisphere of the brain associated with activation in the auditory cortex. More functions associated with language in Brodmann area 22 include producing sentences, semantic processing, and processing of complex sounds. This area of the human brain supports lexical semantic processing and is responsible for language comprehension and production. Wernicke's area is shown to support lexical-semantics because lesions to this area result in difficulties displaying word selection during production of language.

Wernicke's Aphasia

Because Wernicke’s area supports language comprehension in the temporal lobe, lesions to the left

auditory cortex 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 ...

, specifically in BA 22, results in Wernicke’s aphasia. Wernicke’s aphasia, also known as

receptive aphasia Wernicke's aphasia, also known as receptive aphasia, sensory aphasia or posterior aphasia, is a type of aphasia in which individuals have difficulty understanding written and spoken language. Patients with Wernicke's aphasia demonstrate fluent s ...

, is a language disorder characterized as having difficulty comprehending language. This disorder varies in outcomes based on severity and localization of the brain damage, which is mostly commonly due to having a stroke. Patients diagnosed with Wernicke's aphasia are shown to have normal intonation and rate of speech, however have difficulty understanding different words of a language. Many individuals have poor awareness when making errors in speech, but are typically able to produce normal sentence structures when speaking. These sentences produced by patients with Wernicke's aphasia are often difficult for others to understand because of the problems with word selection and comprehension. These difficulties are shown at a lexical level, for example patients often struggle with naming figures due to accessing words from the

lexicon A lexicon is the vocabulary of a language or branch of knowledge (such as nautical or medical). In linguistics, a lexicon is a language's inventory of lexemes. The word ''lexicon'' derives from Koine Greek language, Greek word (), neuter of () ...

Methodology

Methods used to understand functional activity in BA 22 consists mainly of

Functional magnetic resonance imaging Functional magnetic resonance imaging or functional MRI (fMRI) measures brain activity by detecting changes associated with blood flow. This technique relies on the fact that cerebral blood flow and neuronal activation are coupled. When an area o ...

. Functional magnetic resonance imaging (fMRI) is a neuroimaging technique used to understand how language is processed in the BA 22.

Magnetic resonance imaging Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to form pictures of the anatomy and the physiological processes of the body. MRI scanners use strong magnetic fields, magnetic field gradients, and radio wave ...

(MRI) is a technique used to study volume of grey matter and white matter in Brodmann area 22 to find deficits in the structural volume.

Parcellations

Brodmann areas A Brodmann area is a region of the cerebral cortex, in the human or other primate brain, defined by its cytoarchitecture, or histological structure and organization of cells. History Brodmann areas were originally defined and numbered by the ...

are based on cytoarchitectonic parcellation using numbering associated with locations in the brain to illustrate functional activity. BA 22 is separated from the primary and secondary auditory cortex by using cytoarchitectonic parcellation. Connectivity-based parcellations in BA 22 can be broken into three subparts: posterior, middle, and anterior subparts of the superior temporal gyrus. Using connectivity-based parcellations involves connections between white fibers to different areas in the brain. Cytoarchitectonic parecellations and connectivity-based parcellations are two ways of breaking the brain down to the structure and the connection fibers of Brodmann Area 22.

References

Gallery

File:Brodmann area 22 inside lateral sulcus.png, Inside and outside of

lateral sulcus In neuroanatomy, the lateral sulcus (also called Sylvian fissure, after Franciscus Sylvius, or lateral fissure) is one of the most prominent features of the human brain. The lateral sulcus is a deep fissure in each hemisphere that separates the ...

. BA22 is shown in orange.

External links

* For Neuroanatomy of the superior temporal area 22 visi
BrainInfo
* For Neuroanatomy of Brodmann area 22 visi
BrainInfo
{{Prosencephalon 22 Temporal lobe