Disconnexion Syndromes in Animals and Man: Part I

The first part of this paper has been devoted to a consideration of some of the anatomical features of the organization of the cerebral cortex which play a major role in determining some of the features of disturbances of the higher functions in animals as well as men. Stress was laid on the pattern of corticortical connexions in the brains of primates, including man. It was pointed out that disconnexion of cortical regions can be achieved by lesions involving either white matter connexions or by damage to association areas which constitute obligatory way stations between the primary sensory, motor, and limbic regions of the brain in primates. This analysis was applied to a discussion of the agnosias in the subhuman primates. In the last portions of this paper attention was turned to the human brain and to those anatomical features which underlie the development of language. Examples were given of specific syndromes which could best be interpreted as resulting from disconnexion. Part II of the paper will be devoted primarily to a discussion of further applications of the concept of disconnexion to disturbances of the higher functions in man, including the agnosias, the apraxias, and certain aphasic syndromes. A more complete summary of the entire discussion will be found at the end of Part II. © 2010 Springer Science+Business Media, LLC.