Two levels of functional heterogeneity of the neostriatum.

Autoradiography following administration of 2-deoxy-[14C]glucose has shown that penicillin-induced epileptic foci in the cerebral cortex selectively coactivate associated neostriatal regions. The present material demonstrates that this coactivation may appear in patches in the rat neostriatum. Activity from a cortical area seems to spread first to islands of the associated neostriatal region and may either spread gradually to the surrounding 'matrix' or not involve the 'matrix' for tenths of minutes. The regionally restricted functional patchiness lends additional support to the notion that the neostriatum, like the neocortex, can be divided into regions which consist of modules.