[A dynamic neuropsychological approach].

There are at least two approaches in evaluating neuropsychological patients. One is to analyze negative symptoms and find a correlation between a damaged brain lesion and a lost function. The other is to focus on the nature of positive symptoms and find a principle ruling a behavioral change caused by a lesion. Although both approaches are equally important, I focused on the latter approach in this symposium. Two syndromes, i.e. forced manipulation of tools and hyperlexia are interpreted in terms of the rivalry between the top-down process of inhibition and bottom-up process of stimulus processing, resulting in the predominance of the latter. Two other symptoms, i.e. misperception in a case of associative visual agnosia and habitual behavior in a frontal damaged-dementia are interpreted in the same terms, but resulting in the predominance of the top-down process. These syndromes clearly illustrate that the behavior is organized on the dynamic balance between the information generated internally and the one coming in from the environment.