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Backward masking and visual mismatch negativity: Electrophysiological evidence for memory-based detection of deviant stimuli


  • This research was supported by the National Scientific Foundation of Hungary (OTKA T-047038). We thank for Lívia Pató for her help.

Address reprint requests to: István Czigler, Institute for Psychology of the Hungarian Academy of Sciences, 1394 Budapest, P.O. Box 398, Hungary. E-mail:


Sequences composed of two different colored checkerboard patterns (standard and deviant) were presented to adults. Each pattern was followed by a mask with stimulus onset asynchronies (SOAs) varying between 14 and 174 ms. ERPs were recorded to the deviant and standard stimuli while the participants detected changes of a cross, which was continuously present at the center of the screen. In further experiments, the participants performed a Go-NoGo task detecting the deviant checkerboards. Deviant stimuli elicited an occipital negative component with 124–132 ms mean latency (the visual mismatch negativity, vMMN) at test (standard or deviant)-to-mask SOAs longer than 27 ms. No vMMN amplitude increase was observed beyond 40 ms test-to-mask intervals, whereas detection of deviant checkerboard patterns improved up to 174-ms SOA. Therefore the processes underlying vMMN elicitation cannot fully explain the overt detection of visual deviance.