Introduction In an earlier paper in this program of studies on the organization of thalamo-cortical projections evidence has been presented that thelateral dorsalnucleus represents a caudal member of the group of nuclei which project upon the limbic cortex—thelimbicnuclei.22This interpretation of the position and main projection of the lateral dorsal nucleus is not in accord with the views in the extant literature.9,11,12,18,21That the lateral dorsal nucleus does project to cortex is apparent from experimental studies in the monkey1,14,21and pathological material in the human.3,12,13,17In the recorded human cases the cortical lesions have been quite extensive. From such material only the most inferential conclusions can be drawn with regard to the cortical projection field of the lateral dorsal nucleus. A human brain in the collection of the Warren Anatomical Museum (NP Series MU-5-57) with a circumscribed old infarct involving the praecallosal