Further, these regions respond during mental imagery of big and small objects, which is a characteristic property of other nearby category-selective regions. Finally,

we find that these regions reflect information about the category of the object rather than how big the object was conceived. Broadly, these results show that real-world size this website is a large-scale dimension that differentiates distributed object representations in occipitotemporal cortex. We propose a potential account of this organization, in which the size of objects in the world naturally give rise to systematic biases in visual experience which are extracted in early visual areas and ultimately dictate where high-level object representations will be in anterior occipitotemporal cortex. In Experiment 1a, observers were presented with images Epacadostat of isolated big objects (e.g., car, piano) and isolated small objects (e.g., strawberry, safety pin), presented at the same retinal size on the screen (Figure 1A; for all stimuli see Figure S1 available online; see Experimental Procedures). The experiment consisted of one run of 8.8 min

of scanning, during which 200 distinct big objects and 200 distinct small objects were presented in a standard blocked design (see Experimental Procedures). To compare the neural response of big and small objects, we conducted a size-preference map analysis and a whole-brain contrast analysis. In the first analysis, we visualized the spatial distribution

of small and big object preferences across occipitotemporal cortex. Size-preference maps were computed reflecting whether the voxels had a preference for big objects (blue) or small objects (orange) within an object-responsive mask (see Experimental Procedures), and these are shown on an inflated cortical surface in Figure 1. We observed a striking large-scale organization along the ventral surface, evident at the group level and at the single-subject level, with big and small object preferences arranged in a medial to lateral organization across both hemispheres. Further, not this organization was mirrored along the lateral surface of the cortex, with small to big object preferences arranged from inferior to superior (Figures 1B and 1C). Importantly, these data should not be interpreted as evidence that big and small objects are represented in separate swaths of cortex. Both big and small objects activate most of this object-responsive cortex to varying degrees, illustrated in Figures 2, consistent with accounts of distributed activation profiles of these objects (e.g., Haxby et al., 2001). However, voxels with a big-object preference are consistently found along medial ventral temporal cortex, while voxels with a small-object preference were consistently found along lateral temporal cortex (Figures 2C and 2D).