Figure 2.

Procedure of fMRI scanning and follow-up awareness assessment. For each fMRI trial (A), a cross (900 ms), a forward mask (133 ms), a stimulus picture (33 ms), and a backward mask (133 ms) were presented sequentially. During the awareness assessment (B), the sandwich-masked picture was presented and subjects were asked to judge whether the content of the masked picture was a nonhuman animal or an object, and whether the concept depicted by the picture could be placed in a shoe box based on its actual size.