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This review summarizes our findings obtained from over 15 years of research on parietal–frontal networks involved in the dorsal stream of cortical processing. We have presented considerable evidence for the existence of similar, partially independent, parietal–frontal networks involved in specific motor actions in a number of primates. These networks are formed by connections between action‐specific domains representing the same complex movement evoked by electrical microstimulation. Functionally matched domains in the posterior parietal (PPC) and frontal (M1‐PMC) motor regions are hierarchically related. M1 seems to be a critical link in these networks, since the outputs of M1 are essential to the evoked behavior, whereas PPC and PMC mediate complex movements mostly via their connections with M1. Thus, lesioning or deactivating M1 domains selectively blocks matching PMC and PPC domains, while having limited impact on other domains. When pairs of domains are stimulated together, domains within the same parietal–frontal network (matching domains) are cooperative in evoking movements, while they are mainly competitive with other domains (mismatched domains) within the same set of cortical areas. We propose that the interaction of different functional domains in each cortical region (as well as in striatum) occurs mainly via mutual suppression. Thus, the domains at each level are in competition with each other for mediating one of several possible behavioral outcomes. [ABSTRACT FROM AUTHOR]

In prosimian galagos, the posterior parietal cortex (PPC) is subdivided into a number of functional domains where long‐train intracortical microstimulation evoked different types of complex movements. Here, we placed anatomical tracers in multiple locations of PPC to reveal the origins and targets of thalamic connections of four PPC domains for different types of hindlimb, forelimb, or face movements. Thalamic connections of all four domains included nuclei of the motor thalamus, ventral anterior and ventral lateral nuclei, as well as parts of the sensory thalamus, the anterior pulvinar, posterior and ventral posterior superior nuclei, consistent with the sensorimotor functions of PPC domains. PPC domains also projected to the thalamic reticular nucleus in a somatotopic pattern. Quantitative differences in the distributions of labeled neurons in thalamic nuclei suggested that connectional patterns of these domains differed from each other. [ABSTRACT FROM AUTHOR]