Projections from the claustrum to the prelunate gyrus in the monkey

In order to determine whether the cells in the monkey claustrum which project to visual area V4 are found in the same territory as cells projecting to other visual areas, we made injections of the retrograde fluorescent tracer diamidino yellow into area V4 in two monkeys. Injections of a second tracer, fast blue, were also made in area PM, an area just medial to area V4 on the prelunate gyrus, in one animal. Area V4 injections labeled cells in ventral claustrum over about 5-6 mm of its anterior-posterior extent. The more medial prelunate injection labeled cells in adjacent dorsal and more lateral claustrum. These results, together with data from other studies, suggest that in the monkey, as in the cat, there is a "visual" region of claustrum that is interconnected with multiple visual areas including V1, V2, V4, MT, FST, MST, TEO and TE. The data also suggest that dorsal and lateral to this region is another zone which is connected with different visual areas, including several in posterior parietal cortex.