Topographic organization and collateralization of claustrocortical projections in the rat.

The organization of the claustrocortical projections was examined in the rat using a fluorescent retrograde labeling technique. From injections of three different fluorescent tracers into the occipital, frontal and cingulate cortices, claustocortical projections were revealed to be topographically organized in both the rostrocaudal and dorsoventral direction. The dorsoventral topography is similar to that of the primates, but is different from that of the cat. On the basis of a quantitative analysis of the double and triple labeling of single claustral neurons, significant collateralization of the claustrocortical projections is referred.