Functional-imaging studies of the 19th Century neurological model of language.

This paper will consider the consistencies and disparities between the classic 19(th) Century model of language and the results of functional neuro-imaging studies on auditory and visual word repetition. The functional imaging studies show that, as predicted by the 19(th) Century neurologists, auditory and visual word repetition engage perisylvian regions in the left posterior superior temporal and posterior inferior frontal cortices. More specifically, the roles that Wernicke and Broca assigned to these regions lie respectively in the upper banks of the left posterior superior temporal sulcus and the left anterior insula/frontal operculum. In addition, a region in the left posterior inferior temporal cortex is activated for word retrieval and provides a second route to reading, emphasised by 20(th) Century cognitive models of language. There is no firm evidence as yet to link the function of a visual word form area to a specific neural substrate. The angular gyrus, previously linked to the visual word form system, is shown to be part of a distributed semantic system that can be accessed by objects and faces as well as speech. Overall, functional neuroimaging demonstrates that the 19(th) Century neurological model of language is remarkably insightful.