| Noun | 1. | trigonum cerebrale - an arched bundle of white fibers at the base of the brain by which the hippocampus of each hemisphere projects to the contralateral hippocampus and to the thalamus and mamillary bodies carina fornicis - ridge on the lower surface of the fornix of the brain limbic brain, limbic system, visceral brain - a system of functionally related neural structures in the brain that are involved in emotional behavior |