The execution of one simple task is produced by the coordination of various regions and functional areas within the brain. Using language as a focus, this essay will debunk the myth that only 10% of the human brain is used by explaining both the receptive and expressive elements of conducting a conversation, with reference to anatomical areas of the human brain. The aphasic disorders created through neural damage as well the double language dissociations present will prove that much of the brain is being used most of the time. Language is one of the most complex cognitive behaviours (Gazzaniga, 2002), involving the coordination of separate brain areas when executing one simple cognitive task, such as talking or listening (Kalat, 2013). Damage to any of these areas will result in a language disorder, such as aphasia. Aphasia refers to the collective deficits in language comprehension and production that are caused by neurological damage. Problems with the language-processing mechanisms is referred to as primary aphasia, while secondary aphasia results from memory impairments, attention disorders, or perceptual problems (Gazzaniga, 2002). For the purpose of this essay, only primary aphasias will be discussed.
Considering speech production first, this action takes place in two steps. Beginning within the frontal lobe, is an arch of tissue referred to as the primary motor cortex which directs the body's muscles, the rest is comprised of frontal association areas – within which (specifically the left) Broca's area is found and is referred to as a speech centre (Coon & Mitterer, 2012). Typically associated with speech output (Gazzaniga, 2002), Broca's area, is not solely responsible for word combination and articulation. Damage to Broca's area is typically known as Broca's aphasia, but considering recent studies, it is evident that isolated damage to Broca's area does not result in full blown aphasia, but merely brief language impairments (Banich, 2011).