Differential sensitivity for house pictographs and Chinese logographs in the 'parahippocampal place area'

The 'parahippocampal place area, PPA' within parahippocampal cortex is generally implicated in perceiving the local visual environment. This region responds selectively and automatically in functional magnetic resonance imaging (fMRI) to house images. Previous studies have indicated that the house-selective response in the PPA can be explained by selectivity for low-level features of the visual stimuli, such as geometric structure and high special frequency (SF). However, it remains unclear which of the two visual features of stimuli contributes more to the house-selective response in the PPA. To address this issue, we compared the PPA response to house pictographs and Chinese logographs with two different levels of white noise. fMRI was used to record the subjects' PPA activation during category discrimination task between house and word. As a result, the PPA showed significant main effect of category but not noise level. The results suggest that the PPA is more tuned to geometrical structure of visual stimuli than their high SF features.