Last Updated on Sep 03, 2014

Arcuate Fasciculus

Arcuate fasciculus is the connection between the expressive and comprehensive language and is useful in repetition of speech and also carrying a meaningful conversation.

Arcuate Fasciculus is a bundle of axons, the white matter that forms the connection between expressive and comprehensive language areas in the brain. These axons connect the lateral temporal cortex and inferior parietal cortex to locations in the frontal lobe on each side. In this way, connection is established between Broca’s area in the inferior frontal gyrus and Wernicke’s area in the posterior superior temporal gyrus. On an average, a larger area of arcuate fasciculus is seen in the dominant hemisphere in the human beings.

A recent discovery provides anatomical evidence for existence of two pathways of arcuate fasciculus between Broca’s and Wernicke’s areas. One deep and direct connection between the language areas is found. A shallower one consists of two segments, the anterior one connecting frontal cortex with inferior parietal cortex and posterior segment connecting the Wernicke’s area with the inferior parietal cortex, connection being established indirectly.

Significance of location: Arcuate fasciculus is found to be significantly primitive or not present in creatures other than human beings. The nerves connect the Broca’s area to the Wernicke’s area, thus connecting the expressive and comprehensive skills of the individual to be able to produce meaningful conversations and situational speech.

Damage or lesion in the arcuate fasciculus results in conduction aphasia. Damage to the direct pathway is characterized by paraphasic speech production and intact auditory comprehension. However, the person is unable to repeat phrases spoken to them. This happens because of the broken connection between the language areas. Damage to the indirect pathway impairs comprehension, while retaining the ability to repeat speech.

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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