Cognitive neuropsychology and functional brain imaging: implications for functional and anatomical models of cognition

We discuss the relations between functional imaging and cognitive neuropsyc hological research. We begin by elaborating on some of the problems of trad itional neuropsychological research, which attempted to provide accounts of cognitive performance at a neural as well as at a functional level of desc ription. The difficulties in making neural-level arguments from neuropsycho logical data include: problems of associated deficits, problems due to inte ractive effects between brain regions, problems with analyses based on beha vioural syndromes, problems due to the influence of compensatory strategies , and problems in separating damaged from disconnected representations. We discuss how cognitive neuropsychology by-passed many of these problems by e mphasising functional rather than neural-level theories, though problems wi th inferences at the neural-level remain. We then consider the contribution that functional imaging can make to cognitive neuropsychology. Using evide nce drawn from studies of language, object recognition and visual attention , we argue that functional imaging complements cognitive neuropsychology by : (i) not being reliant on accidents of nature and by enabling effects of l esions on 'distant' neural areas to be measured, (ii) revealing the brain s ystems necessary and sufficient for a given task, (iii) providing tests of neural-level models of cognition, and by (iv) providing novel evidence on t he mechanisms of functional recovery in patients. In addition to this, imag ing studies can contribute directly to functional-level theories, by provid ing converging evidence on the neural locus of cognition - knowing 'where' can allow new inferences about 'how' a given task is performed. (C) 2001 El sevier Science B.V. All rights reserved.