Fiber system linking the mid-dorsolateral frontal cortex with the retrosplenial/presubicular region in the rhesus monkey

The present study investigated the origin, course, and terminations of the association fiber system linking the frontal cortex with the hippocampal sy stem by means of the cingulum bundle. Injections of tritiated amino acids w ere placed within individual cytoarchitectonic areas of the frontal cortex in the rhesus monkey. It was demonstrated that the mid-dorsolateral frontal cortex (areas 46, 9/46, and 9) and its medial extension (medial areas 9 an d 9/32) is the origin of a specific fiber pathway, running posteriorly as p art of the cingulum bundle, and terminating mainly in the retrosplenial are a 30 and the posterior presubiculum. This fiber bundle therefore provides t he anatomical substrate of a functional interaction between the mid-dorsola teral frontal cortex and the hippocampal memory system for the monitoring o f information within working memory. J. Comp. Neurol. 407:183-192, 1999. (C ) 1999 Wiley-Liss, Inc.