Comparative fMRI reveals differences in the functional organization of the visual cortex for animacy perception in dogs and humans
The animate-inanimate category distinction is one of the general organizing principles in the primate high-level visual cortex. Much less is known about the visual cortical representations of animacy in non-primate mammals with a different evolutionary trajectory of visual capacities. To compare the functional organization underlying animacy perception of a non-primate to a primate species, here we performed an fMRI study in dogs and humans, investigating how animacy structures neural responses in the visual cortex of the two species. Univariate analyses identified animate-sensitive bilateral occipital and temporal regions, non-overlapping with early visual areas, in both species. Multivariate tests confirmed the categorical representations of animate stimuli in these regions. Regions sensitive to different animate stimulus classes (dog, human, cat) overlapped less in dog than in human brains. Together, these findings reveal that the importance of animate-inanimate distinction is reflected in the organization of higher-level visual cortex, also beyond primates. But a key species difference, that neural representations for animate stimuli are less concentrated in dogs than in humans suggests that certain underlying organizing principles that support the visual perception of animacy in primates may not play a similarly important role in other mammals.