Time Courses of Attended and Ignored Object Representations

摘要

Selective attention prioritizes information that is relevant tobehavioral goals. Previous studies have shown that attendedvisual information is processed and represented more efficiently,but distracting visual information is not fully suppressed,and may also continue to be represented in the brain. In naturalvision, to-be-attended and to-be-ignored objects may be presentsimultaneously in the scene. Understanding precisely how eachis represented in the visual system, and how these neural representationsevolve over time, remains a key goal in cognitiveneuroscience. In this study, we recorded EEG while participantsperformed a cued object-based attention task that involvedattending to target objects and ignoring simultaneouslypresented and spatially overlapping distractor objects. We performedsupport vector machine classification on the stimulusevokedEEG data to separately track the temporal dynamics oftarget and distractor representations. We found that (1) bothtarget and distractor objects were decodable during the earlyphase of object processing (～100 msec to ～200 msec aftertarget onset), and (2) the representations of both objects weresustained over time, remaining decodable above chance until～1000-msec latency. However, (3) the distractor object informationfaded significantly beginning after about 300-msec latency.These findings provide information about the fate of attendedand ignored visual information in complex scene perception.