Cortical organization of language.

Recent data obtained by various methods of clinical investigations suggest an organization of language in the human brain involving compartmentalization into separate systems subserving different language functions. Each system includes multiple essential areas localized in the frontal and temporoparietal cortex of the dominant hemisphere, as well as widely dispersed neurons. All components of a system are activated in parallel, possibly by ascending thalamocortical circuits. The features peculiar to cerebral language organization include not only the lateralization of essential areas to one hemisphere, but also a substantial variance in the individual patterns of localization within that hemisphere, a variance that in part relates to individual differences in verbal skills.