Specialisation for language emerges from the integration of nonverbal neural systems

Cathy Price

Abstract

The neuronal infrastructure for language processing was initially identified on the basis of lesion studies. Speech perception was associated with Wernicke's area in the left posterior superior temporal cortex while speech production was associated with Broca's area in the left inferior frontal cortex. Functional imaging studies have revealed many other brain areas that participate in language tasks. In my talk, I will consider whether any of these areas are specific to language by comparing verbal and nonverbal perception and production. Speech perception activates discrete areas in the left superior temporal cortex but the same areas are engaged by unfamiliar nonverbal melodies. Speech production relative to nonverbal mouth movements activates left inferior frontal and posterior superior temporal areas. The left posterior temporal area corresponds to that involved in auditory perception while the left inferior frontal area corresponds to that activated when nonverbal hand movements are generated on the basis of the structural shape of objects. Taken together, these findings suggest that there are no areas of the brain that are specific to verbal processing. Instead language emerges by virtue of brain regions, such and Wernicke's and Broca's areas, that serve to integrate articulation areas with auditory and visual inputs.