| Human is able to rapidly classify object categories such as animals or vehicles in new scenes that are presented very briefly.A number of evidences have suggested the rapid classification is mainly to distinguish animals from other categories.An unresolved question is whether the outstanding ability reflects the views that traditional general theory implicitly contain,that is,categories of all objects are represented equally no matter they are processed roughly or precisely.Alternatively,the representation of some categories has greater advantages and more integrity compared to that of others categories in a certain period of time.Therefore,it is necessary to directly compare the representation degree of different categories in the process of rapid object classification.Here,this question was addressed by using a noise detection task in which subjects processed objects as little as possible and measuring functional magnetic resonance imaging(fMRI)responses to animate-and inanimate-objects between extremely short classification times(33ms)and longer classification times(500ms).With multi-voxel pattern analysis(MVPA),the visual rapid object classification was examined according to the difference of the classified neural representation in the short presentation time.In addition,two approaches were employed to establish ROI-contrasting task with noise conditions;drawing a cube to exclude the possibility that the category representation in the selected ROI may occur a stronger category effect.The whole brain analysis showed the animate-and inanimate-objects preferring regions under the two conditions were consistent with previous studies.The MVPA of neural activity in ventral temporal cortex exhibited the similarity of representation of animate objects was significantly higher than that of inanimate object under the two conditions.The findings revealed that there was earlier inequality across categories in the neural representation of rapid object classification.And its cognitive function may be driven by the high efficiency of animate representation.Together,these findings indicated that unlike the traditional idea at a certain point in time,animate and inanimate objects obtained the equal degree of representation,while animate objects were represented in a more complete way in the visual system. |
