Functional activation studies of word processing in the recovery from aphasia.

Some reviews on theories of recovery in aphasia put an emphasis on neural network models based on empirical data from evoked-potentials in aphasia as an approach to mapping recovery of cognitive function to neural structure. We will focus here on what we call an "anatomical" approach to look at recovery in aphasia. "Anatomical" theories of recovery stated by classical aphasiologists have contributed to the understanding of language representations in the human brain. But many aspects of these theories can only be investigated by using modern techniques of lesion analysis, psychometric assessment and functional imaging. Whereas structure-function relations have been primarily established by looking for the association of deficit symptoms with certain lesions, functional activation methods offer a means to study more directly the functional anatomy of recovered or retained functions in neuropsychological patients. To falsify or build up anatomical theories of recovery we will propose a stepwise approach of inference. The methodological pitfalls of this approach will be discussed by focussing on anatomical hypotheses of semantic word comprehension and its impairment and recovery in aphasia.