Further studies on the cortical connections of the Tegu lizard

The efferent fiber connections of the caudal half of the cerebral cortex, the lateral cortex and the pallial thickening were studied using the Nauta-Gygax and Fink-Heimer techniques. The following observations were made, (1) In the caudal half of the hemisphere corticoseptal and corticohypothalamic fibers originate from the small-celled part of the mediodorsal cortex and the thickened caudal part of the dorsal cortex in its whole mediolateral extent. (2) The dorsal cortex in the middle of the hemisphere projects by way of both the pre- and postcommissural fornices. Its rostral pole distributes its fibers solely to the postcommissural fornix, whereas its caudal part projects via the precommissural fornix. (3) The posterior pallial commissure carries fibers that arise caudally in the small-celled part of the mediodorsal cortex and terminate in the contralateral ventral cortex. (4) Projections to the dorsal striatum originate from the lateral cortex, the dorsal cortex and the superficial portion of the pallial thickening. In addition, the latter two zones project to the nucleus accumbens. (5) The deep portion of the pallial thickening projects to the ventral striatum.