Associational projections of the anterior midline cortex in the rat: intracingulate and retrosplenial connections

• Published in: Brain research Vol. 825; no. 1; pp. 1 - 13
• Main Authors: Fisk, Gary Dale, Wyss, James Michael
• Format: Journal Article
• Language: English
• Published: London Elsevier B.V 17.04.1999; Amsterdam Elsevier; New York, NY
• Subjects: Anatomy; Animals; Anterior cingulate cortex; Anterograde neuroanatomical tracing; Axons - physiology; Biological and medical sciences; Central nervous system; Cerebral Cortex - cytology; Dorsal peduncular cortex; Fundamental and applied biological sciences. Psychology; Gyrus Cinguli - cytology; Infralimbic cortex; Limbic cortex; Male; Neural Pathways; Phaseolus vulgaris; Phaseolus vulgaris leucoagglutinin; Phytohemagglutinins; Precentral medial cortex; Prelimbic cortex; Rats; Rats, Sprague-Dawley; Retrosplenial cortex; Vertebrates: nervous system and sense organs; Anterior cingulate cortex; Infralimbic cortex; Anterograde neuroanatomical tracing; Prelimbic cortex; Dorsal peduncular cortex; Retrosplenial cortex; Phaseolus vulgaris leucoagglutinin; Limbic cortex; Precentral medial cortex; Vertebrata; Cerebral cortex; Mammalia; Rat; Rodentia; Central nervous system; Projection; Anatomy; Brain (vertebrata)
• ISSN: 0006-8993; 1872-6240
• DOI: 10.1016/S0006-8993(99)01182-8

Past studies indicate that distinct areas of anterior midline cortex in the rat contribute to diverse functions, such as autonomic nervous system regulation and learning, but the anatomical substrate for these functions has not been fully elucidated. The present study characterizes the associational connections within the midline cortex of the rat by using the anterograde transport of Phaseolus vulgaris leucoagglutinin and Fluororuby. The prelimbic area and the rostral part of the anterior cingulate area (both dorsal and ventral subdivisions) are extensively interconnected with each other. In addition, the caudal half of anterior cingulate cortex has extensive projections to precentral medial cortex and caudally directed projections to retrosplenial cortex. Other cortical areas within anterior midline cortex have relatively limited cortical–cortical projections. The infralimbic, dorsal peduncular, and medial precentral cortices have dense intrinsic projections, but have either very limited or no projections to other areas in the anterior midline cortex. Although it has been suggested that cortical–cortical projections from anterior cingulate cortex and prelimbic cortex to infralimbic cortex may be important for linking learning processes with an autonomic nervous system response, the paucity of direct projections between these areas calls this hypothesis into question. Conversely, the results suggest that the anterior midline cortex contains two regions that are functionally and connectionally distinct.