Wernicke's area

Wernicke's area (ˈvɛərnᵻkə; ˈvɛɐ̯nɪkə), 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 Broca's area, which is primarily involved in the production of language. It is traditionally thought to reside in Brodmann area 22, which is located in the superior temporal gyrus in the dominant cerebral hemisphere, which is the left hemisphere in about 95% of right-handed individuals and 70% of left-handed individuals. Damage caused to Wernicke's area results in receptive, fluent aphasia. This means that the person with aphasia will be able to fluently connect words, but the phrases will lack meaning. This is unlike non-fluent aphasia, in which the person will use meaningful words, but in a non-fluent, telegraphic manner. Wernicke's area is traditionally viewed as being located in the posterior section of the superior temporal gyrus (STG), usually in the left cerebral hemisphere. This area encircles the auditory cortex on the lateral sulcus, the part of the brain where the temporal lobe and parietal lobe meet. This area is neuroanatomically described as the posterior part of Brodmann area 22. However, there is an absence of consistent definitions as to the location. Some identify it with the unimodal auditory association in the superior temporal gyrus anterior to the primary auditory cortex (the anterior part of BA 22). This is the site most consistently implicated in auditory word recognition by functional brain imaging experiments. Others include also adjacent parts of the heteromodal cortex in BA 39 and BA40 in the parietal lobe. Despite the overwhelming notion of a specifically defined "Wernicke's Area," the most careful current research suggests that it is not a unified concept. While previously thought to connect Wernicke's area and Broca's area, new research demonstrates that the arcuate fasciculus instead connects to posterior receptive areas with premotor/motor areas, and not to Broca's area.