Cortical connections of the dorsomedial visual area in Old World macaque monkeys

The connections of a wedge of densely myelinated cortex along the dorsomedi al border of V2 were determined by injecting tracers into this region in ma caque monkeys. According to previous descriptions, this cortex would consti tute parts of dorsal V3 and V3A, or a dorsomedial visual area, DM, homologo us to the DM described in prosimians and New World monkeys. Injections of w heat germ agglutinin conjugated to horseradish peroxidase or various fluore scent tracers demonstrated connections with architectonically defined V1, V 2, and the middle temporal area, as well as regions of visual areas known a s the ventral posterior parietal area, the rostral dorsolateral area or ros tral V4, ventral posterior cortex and more rostral cortex in the ventral te mporal lobe, and medial and dorsointermediate areas. Other sparser and less consistently revealed connections were with the medial superior temporal a rea, the area of the fundus of the superior temporal sulcus, and the caudal dorsolateral area. Distributions of labeled cells in V1 varied in relation ship to the pattern of cytochrome oxidase blobs and interblobs in a manner suggesting a heterogeneous pattern of terminations from blob and interblob regions within DM. Major similarities in overall connections of the DM regi on in macaques with DM connections described in New World monkeys and prosi mian galagos support the conclusion that the same visual area, DM, has been identified in all these primates. J. Comp. Neurol. 406:487-502, 1999. (C) 1999 Wiley-Liss, Inc.