The pulvinar regulates information transmission to cortex and communication between cortical areas. The way the pulvinar interacts with cortex is governed by its intrinsic organization. Here, we show using fMRI that the human pulvinar is functionally heterogeneous, broadly separated into dorsal and ventral subdivisions based on characterization of response properties and functional connectivity with cortex. These differences mirrored the organization of the dorsal and ventral streams of visual cortex. The ventral subdivision of the pulvinar was functionally coupled with occipital and temporal cortex. The dorsal subdivision of the pulvinar was functionally coupled with frontal and parietal cortex. The dorsal subdivision was also coupled with the human-specific tool network and to the default mode network. The spatial organization of pulvino-cortical coupling reflected both the functional similarities and anatomical distances between cortical areas. Together, the human pulvinar appears to represent the entire visual system and the principles that govern its organization, though in a spatially compressed form.. CC-BY 4.0 International license It is made available under a (which was not peer-reviewed) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity.The copyright holder for this preprint . http://dx.doi.org/10.1101/205039 doi: bioRxiv preprint first posted online Oct. 18, 2017; 3 IntroductionThe pulvinar is anatomically heterogeneous and extensively interconnected with visual cortex. As a general principle, cortical areas that are directly connected are also indirectly interconnected via the pulvinar (Shipp, 2003). Through this connectivity, it is thought that the pulvinar regulates corticocortical communication (Jones, 2001;Shipp, 2003;Saalmann et al., 2012). The function of the pulvinar's influence on cortex is governed by its organization. Most of our understanding about the pulvinar comes from studies in non-human primates, though the broad organization of the human pulvinar appears to be similar to other primate species (Fig. 1). Across primates, the ventral pulvinar contains two well-defined maps of visual space (Allman et al., 1972;Bender, 1981;Li et al., 2013;. The ventral pulvinar is mainly connected with occipital visual areas and the dorsal pulvinar is connected with parietal and frontal regions (Shipp, 2003;Kaas and Lyon, 2007;Schmahmann and Pandya, 2008). Taken together, these data suggest a general distinction between the dorsal and ventral pulvinar.The organizational principles governing pulvino-cortical connectivity may be guided by several factors. Within the monkey pulvinar, anatomical cortical connections appear to be topographically organized with neighboring parts of cortex projecting to neighboring parts of the pulvinar (Baizer et al., 1993). In the dorsal pulvinar, posterior parietal areas project to lateral portions of the dorsal pulvinar with anterior parietal areas projecting to more medial portions of the dorsal pulvinar (Fig. 1b) (Sc...