LONG ASSOCIATION FIBERS IN CEREBRAL HEMISPHERES OF MONKEY AND CHIMPANZEE

Abstract

By applying strychnine locally to the cerebral cortex of the monkey and chimpanzee, and recording the electrical activity, the origin and termination of homologues of 3 of the well-defined long association bundles of the human cerebral cortex were disclosed. From area 8, the frontal suppressor area, there arises a tract leading to area 18, the parastriate area; this is probably part of the superior longitudinal fasciculus of Burdach. From area 18 there arises a tract leading to area 20, on the inferior temporal convolution; it is usually called the fasciculus longitudinalis inferior, and may comprise also what anatomically has been called the vertical occipital fasciculus of Wernicke. There is a tract arising from the area orbitalis agranularis (called area 47 in the human brain) passing to the tip of the temporal lobe (called area 38 in the human brain); it is ordinarily called the fasciculus uncinatus. Each of these pathways normally conducts in one direction only.