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Brain: Wernicke's area
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Approximate location of Wernicke's area highlighted in grey
NeuroNames ancil-252

Wernicke's area ("Wernicke" English pronunciation: /ˈvɛrnɪkə/ or /ˈvɛrnɪkiː/; German: [ˈvɛʁniːkə]) is one of the two parts of the cerebral cortex linked since the late nineteenth century to speech (the other is the Broca's area). It is involved in the understanding of written and spoken language. It is traditionally considered to consist of the posterior section of the superior temporal gyrus in the dominant cerebral hemisphere (which is the left hemisphere in about 90% of people).

Contents

Location

The Wernicke's area is classically located as the posterior section of the superior temporal gyrus (STG) in the left (or dominant) cerebral hemisphere. This area encircles the auditory cortex on the Sylvian fissure (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 its location.[1] Some identify it with the unimodal auditory association in the superior temporal gyrus anterior to the primary auditory cortex.[2] Others include also adjacent parts of the heteromodal cortex in BA 39 and BA40 in the parietal lobe.[3]

While previously thought to connect Wernicke's area and Broca's area, new research demonstrates that the AF instead connects to posterior receptive areas with premotor/motor areas, and not to Broca's area.[4]

Wernicke and aphasia

Wernicke's area is named after Carl Wernicke, a German neurologist and psychiatrist who, in 1874, hypothesized a link between the left posterior section of the superior temporal gyrus and the reflexive mimicking of words and their syllables that associated the sensory and motor images of spoken words.[5]

He did this on the basis of the location of brain injuries that caused aphasia. Receptive aphasia in which such abilities are preserved is now sometimes called Wernicke's aphasia. In this condition there is a major impairment of language comprehension, while speech retains a natural-sounding rhythm and a relatively normal syntax. Language as a result is largely meaningless (a condition sometimes called fluent or jargon aphasia). However, it is now known that "Wernicke's aphasia" is not caused by damage to the Wernicke's area.[1][6]

Right homologous area

Research using Transcranial magnetic stimulation suggests that the area corresponding to the Wernicke’s area in the non-dominant cerebral hemisphere has a role in processing and resolution of subordinate meanings of ambiguous words—such as (‘‘river’’) when given the ambiguous word (‘‘bank’’). In contrast, the Wernicke's area in the dominant hemisphere processes dominant word meanings (‘‘teller’’ given ‘‘bank’’).[7]

Modern views

Neuroimaging suggests the functions earlier attributed to the Wernicke's area occur more broadly in the temporal lobe and indeed happen also in the Broca's area.

There are some suggestions that middle and inferior temporal gyri and basal temporal cortex reflect lexical processing ... there is consensus that the STG from rostral to caudal fields and the STS constitute the neural tissue in which many of the critical computations for speech recognition are executed ... aspects of Broca’s area (Brodmann areas 44 and 45) are also regularly implicated in speech processing.

... the range of areas implicated in speech processing go well beyond the classical language areas typically mentioned for speech; the vast majority of textbooks still state that this aspect of perception and language processing occurs in Wernicke’s area (the posterior third of the STG).[8]

Footnotes

  1. ^ a b Bogen JE, Bogen GM (1976). "Wernicke's region—Where is it?". Ann. N. Y. Acad. Sci. 280: 834–43. PMID 1070943. http://www3.interscience.wiley.com/resolve/openurl?genre=article&sid=nlm:pubmed&issn=0077-8923&date=1976&volume=280&spage=834.  
  2. ^ Démonet JF, Chollet F, Ramsay S, et al. (December 1992). "The anatomy of phonological and semantic processing in normal subjects". Brain 115 (Pt 6): 1753–68. PMID 1486459. http://brain.oxfordjournals.org/cgi/pmidlookup?view=long&pmid=1486459.  
  3. ^ Mesulam MM (June 1998). "From sensation to cognition". Brain 121 (Pt 6): 1013–52. PMID 9648540. http://brain.oxfordjournals.org/cgi/reprint/121/6/1013.  
  4. ^ Bernal B, Ardila A (September 2009). "The role of the arcuate fasciculus in conduction aphasia". Brain 132 (Pt 9): 2309–16. doi:10.1093/brain/awp206. PMID 19690094. http://brain.oxfordjournals.org/cgi/pmidlookup?view=long&pmid=19690094.  
  5. ^ Wernicke K. (1995). "The aphasia symptom-complex: A psychological study on an anatomical basis (1875)". in Paul Eling. Reader in the History of Aphasia: From (Franz Gall to). 4. Amsterdam: John Benjamins Pub Co. pp. 69–89. ISBN 90-272-1893-5.  
  6. ^ Dronkers NF., Redfern B B., Knight R T. (2000). "The neural architecture of language disorders". in Bizzi, Emilio; Gazzaniga, Michael S.. The New cognitive neurosciences (2nd ed.). Cambridge, Mass: MIT Press. pp. 949–58. ISBN 0-262-07195-9.  
  7. ^ Harpaz Y, Levkovitz Y, Lavidor M (October 2009). "Lexical ambiguity resolution in Wernicke's area and its right homologue". Cortex 45 (9): 1097–103. doi:10.1016/j.cortex.2009.01.002. PMID 19251255. http://linkinghub.elsevier.com/retrieve/pii/S0010-9452(09)00029-X.  
  8. ^ Poeppel D, Idsardi WJ, van Wassenhove V (March 2008). "Speech perception at the interface of neurobiology and linguistics". Philos. Trans. R. Soc. Lond., B, Biol. Sci. 363 (1493): 1071–86. doi:10.1098/rstb.2007.2160. PMID 17890189. PMC 2606797. http://rstb.royalsocietypublishing.org/cgi/pmidlookup?view=long&pmid=17890189.  

See also

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