The cerebral cortex of the brain can be further classified into different brain regions. German anatomist Korbinian Brodmann defined and numbered 52 different regions of the cerebral cortex based on the cytoarchitectural organization of its neurons. These 52 areas are known as Brodmann areas of brain.
In 1861, a French neurosurgeon Paul Broca identified for the first time, the existence of a â€œlanguage centreâ€ in the posterior portion of the frontal lobe of left hemisphere. Now this area is known as Brocaâ€™s area. This was in fact the first area of the brain to be associated with a specific functionâ€”in this case, language.
Ten years later, a German neurologist Carl Wernicke, discovered another part of the brain in the posterior portion of the left temporal lobe. This one known as Wernicke's area involved in understanding language. People who had a lesion at this location could speak, but their speech was often incoherent and made no sense.
Neuroscientists now agree in the left hemisphere of the brain, there is a sort of neural loop that is involved both in understanding and in producing spoken language. At the frontal end of this loop lies Broca's area, which is usually associated with the production of language, or language outputs. At the other end (more specifically, in the superior posterior temporal lobe), lies Wernicke's area, which is associated with the processing of words that we hear being spoken, or language inputs. Broca's area and Wernicke's area are connected by a large bundle of nerve fibers called the arcuate fasciculus.
Brodmann area 44 â€œPars opercularisâ€ and area 45 â€œpars triangularisâ€ are parts of Broca's area. Brodmann area 22 â€œSuperior temporal gyrusâ€ is usually considered to contain the Wernicke's area. Brodmann area 39 â€œAngular gyrusâ€ and area 40 â€œSupramarginal gyrusâ€ are considered by some to be part of Wernicke's area.
Fig 1: Lateral surface of the brain with Brodmann's areas numbered
Fig 2: Medial surface of the brain with Brodmann's areas numbered
Fig 3: The Broca's and Wernicke's area of Brain.