Broca's area

Broca's area, or the Broca area (/ˈbroʊkə/, also UK: /ˈbrɒkə/, US: /ˈbroʊkɑː/), is a region in the frontal lobe of the dominant hemisphere, usually the left, of the brain with functions linked to speech production.

Language processing has been linked to Broca's area since Pierre Paul Broca reported impairments in two patients. They had lost the ability to speak after injury to the posterior inferior frontal gyrus (pars triangularis) (BA45) of the brain. Since then, the approximate region he identified has become known as Broca's area, and the deficit in language production as Broca's aphasia, also called expressive aphasia. Broca's area is now typically defined in terms of the pars opercularis and pars triangularis of the inferior frontal gyrus, represented in Brodmann's cytoarchitectonic map as Brodmann area 44 and Brodmann area 45 of the dominant hemisphere.

Functional magnetic resonance imaging (fMRI) has shown language processing to also involve the third part of the inferior frontal gyrus the pars orbitalis, as well as the ventral part of BA6 and these are now often included in a larger area called Broca's region.

Studies of chronic aphasia have implicated an essential role of Broca's area in various speech and language functions. Further, fMRI studies have also identified activation patterns in Broca's area associated with various language tasks. However, slow destruction of Broca's area by brain tumors can leave speech relatively intact, suggesting its functions can shift to nearby areas in the brain.