Association Centers

ASSOCIATION CENTERS, according to the theory of Flechsig²/, occupy areas of the cerebral cortex; they are characterized by their independence from underlying structures; no irritations from the external world or from internal organs are transmitted to them directly, just as the association centers remain without influence on organs and peripheral musculature. The association centers are connected by a large number of centripetal and centrifugal fibers with areas of the cortex belonging to the projection spheres of the same hemisphere. Flechsig distinguishes three association centers: 1) posterior, encompassing part of the occipital, parietal, and temporal lobes; 2) middle, corresponding to insula Reilii; and 3) anterior, located in the anterior parts of the frontal lobe. The presence of projection fibers in these centers is not denied, but they are present in minimal quantities. The association centers reach exceptional development only in humans. Flechsig attributes to them the highest mental activity; other authors localize in these centers elementary intellectual processes directly connected with sensations; these centers are also called mnemonic centers.