The “Parahippocampal Place Area” Responds Preferentially to High Spatial Frequencies in Humans and Monkeys
Figure 7
PPA activity reflects the spectral variation in natural scenes.
(A and B) Examples of scenes with relatively higher (H scenes) (A) and lower (L scenes) (B) power at high SFs. These two images had the highest (H1) and the lowest (L1) normalized high SF power in our scene image database (see Figure S10 for details). (C and D) The FFT of the H1 (C) and L1 (D) images. The H1 scene had more high SF power (and less low SF power) than the L1 scene. The frequency bias was not confined to specific scene categories (e.g., outdoor versus indoor scenes). (E) PPA was localized based on a blocked-design comparison between scene stimuli and single-object stimuli, in five human subjects. The group-averaged activity map is displayed on a medial view of an averaged inflated cortical surface (right hemisphere). (F) The comparison between H scenes and L scenes revealed a strong fMRI activity for H scenes within PPA. This activity extended posteriorly, in occipito-temporal cortex.