Problems in the Anatomical Understanding of the Aphasias

Abstract

Although it may seem at first to be an odd comparison there is a great similarity between the development of modern genetics and the study of the syndromes resulting from damage to the brain. Although genetics began as a purely ‘functional’ field, in which one dealt with the inheritance of more or less arbitrarily designated ‘characters’, the appearance of the idea of chromosomes with genes placed at specific sites created a change in approach. To paraphrase Wernicke who subtitled his ‘Symptom-Complex of Aphasia’ as ‘A Psychological Study on an Anatomical Basis’ genetics became a functional study on an anatomic basis. The ‘localizationist’ approach to genetics has many of the same potential problems as a localizationist approach to the higher functions. Where is the gene for philoprogenitiveness, and does it control the size of a cortical region subserving this characteristic? Clearly it is not reasonable to expect that every nameable feature will have a chromosomal or a cortical localization. Yet this does not mean that certain other aspects of behavior could not be shown to depend critically on a specific gene or a specific site in the nervous system.