A tiny piano thus becomes a hand-held object; a giant peach becomes a large object or landmark we can move
around. In Experiment 3, we examined whether these regions are tied to the object XAV-939 clinical trial category or whether the response reflects a more abstract concept of conceived size using a mental imagery task. Names of objects were presented aurally to a new set of observers, whose task was to form a mental image of each object. In half of the blocks, observers were told to imagine isolated objects at their typical size when they heard the object names (e.g., peach, piano). In the other half of the blocks, they were told to imagine an isolated object at an atypical size: specifically, they heard the adjective “tiny” for big objects and “giant” for small objects: e.g., “tiny piano,” imagined with the size of matchbox, or “giant peach,” imagined with the size of car (see Experimental
Procedures). Afterwards they were presented with small and big objects visually (as in selleck compound Experiment 1), to independently localize the big and small regions of interest in each subject. When participants imagined big and small objects at their typical sizes, the big and small regions showed more activity to objects with the preferred real-world size (Figure 5; Small-OTS-L: t(7) = 2.4, p = 0.048; Small-LO-L marginal: t(7) = 1.8, p = 0.107; Small-LO-R marginal: t(6) = 2.1, p = 0.083; Big-PHC-L: t(6) = 4.0, p = 0.007; Big-PHC-R: t(7) = 3.2, p = 0.015). These results are consistent with the fundamental and general finding that neural responses in object-selective cortex are similar between perception and imagery (O’Craven and Kanwisher, 2000, Reddy et al., 2010 and Stokes et al., 2009). Further, these results
also demonstrate that our previous results were not driven by pictoral artifacts of the stimuli: here, any perceptual features instantiated via imagery processes MTMR9 are meaningfully tied to object concepts and are not driven by unintentional feed-forward stimulus artifacts. When observers imagined big and small objects in the atypical-size conditions, the big and small regions did not reflect the conceived size of the object. That is, imagining a giant peach still activated the small-preference regions more than imagining a tiny piano (see Figure 4; Small-OTS-L: t(7) = 2.6, p = 0.036; Small-LO-L: t(7) = 2.4, p = 0.048; though not significantly in the right hemisphere Small-LO-R region: t(6) = 0.8, p = 0.45; Big-PHC-L and Big-PHC-R trending: both t(7) = 1.7, p = 0.13; see Table S2 for 2 × 2 ANOVA statistics). These results demonstrate that activity in these big and small regions does not reflect the conceived size of the imagined object—these regions are not reflecting an abstract sense of real-world size independent of the object identity.