Last Updated on Sep 03, 2014

Broca's Area

Expressive language, in the form of grammatically correct and meaningful speech, is processed by Broca’s area and the damage to this area leads to Broca’s aphasia.

Broca's area for Expressive language:

Identifying the language specific areas in the brain started in 1961 with Paul Broca, a French neurosurgeon, who studied the brain of a person who died of a disorder. The deceased person was able to understand spoken language but was not able to speak or express himself in any other way. Neither was he having any kind of facial paralysis that could affect speech. Broca found a significant lesion in the left inferior frontal cortex of the brain. After analyzing eight other similar patients, Broca believed that speech was localized to this area.

The area is now identified as the pars opercularis and pars triangularis of the inferior frontal gyrus. It is represented in Broadmann’s cytoarchitectonic map as areas 44 and 45 in the dominant hemispheres. Further research suggests that Brodmann’s area 44, the pars opercularis, could involve phonological fluency (sounds and words) and the Brodmann’s area 45, the pars triangularis, could involve the semantic fluency (grammatically correct and meaningful speech).

Significance of location: The Broca’s area lies near the motor cortex, thus sends signals to the larynx, tongue and mouth motor areas. These signals are further transmitted to the corresponding muscles to create the sounds.

Damage to or lesion in the Broca’s area causes Broca’s aphasia or expressive aphasia. The affected person is not able to speak fluently, but the ability to understand spoken and written language and gestures is good for simple sentences. However, they may not be able to comprehend complex grammatical sentences. They know what they want to say, but are not able to get it out. Word repetition and anomia (difficulty in getting the exact word) are some of the speech characteristics. The individuals feel frustrated as they are aware of their problem.

References:

  1. Broca's area - (http://en.wikipedia.org/wiki/Broca's_area)
  2. Language processing in the brain - (http://en.wikipedia.org/wiki/Language_processing_in_the_brain)
  3. Arcuate fasciculus - (http://en.wikipedia.org/wiki/Arcuate_fasciculus)
  4. ARCUATE FASCICULUS SIZE AND TRAJECTORY - (http://carta.anthropogeny.org/moca/topics/arcuate-fasciculus)
  5. Wernicke's area - (http://en.wikipedia.org/wiki/Wernicke%27s_area)
  6. Angular gyrus - (http://en.wikipedia.org/wiki/Angular_gyrus)

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