Posterior parietal projections to the intraparietal sulcus of the rhesus monkey.

A cyto- and myeloarchitectonic parcellation of the intraparietal sulcus in the rhesus monkey was correlated with the pattern of afferent connections from the parietal lobe as determined by autoradiographic techniques. Area PEa in the upper bank receives topographically-organized input from the ventral and caudal superior parietal lobule and the medial surface of the parietal lobe. Area POa in the lower bank is the recipient of a projection from the rostral inferior parietal lobule. Area IPd, situated in the depth of the intraparietal sulcus, receives converging input from the caudal superior parietal lobule, medial surface of the parietal lobe, and mid- and caudal inferior parietal lobule. Finally, intrinsic sequences of connections, directed from rostral to caudal and caudal to rostral, exist within both areas PEa and POa, each having a distinctive laminar pattern of origins and terminations.