TY - GEN ID - cogprints1182 UR - http://cogprints.org/1182/ A1 - OADES, Robert D. A1 - DITTMANN-BALCAR, Alexandra Y1 - 1995/// N2 - Introduction: MMN is a negative component resulting from the difference in event-related potential (ERP) waveforms elicited by a standard and a deviant stimulus. It is usually studied in the absence of attentional requirements. Method: Here we compare this measure of perceptual comparison in a nontask situation (3 tones presented) with that obtained in a task requiring focussed attention and response to the third tone. Subjects were 9 male and 16 female healthy volunteers aged 18-25 years Results: MMN amplitude (comparison of standard and deviant irrelevant tones) increased with focussed attention to the third (target) tone and frontal maxima shifted slightly posteriorly. The succeding P3 in the difference waveform increased more posteriorly than frontally confirming continued differential processing of irrelevant stimuli under active conditions. Conclusion: This demonstrates that not only attending to stimuli, but the active processing of irrelevant stimuli (vs passive perception) involves small changes of the amount and distribution of neural activity. i.e. active controlled processing in focussed attention can affect the capacity or distribution of resources even for automatic processing of information (the MMN). PB - Rapid Communications of Oxford Ltd KW - attention KW - focused attention KW - event-related potential KW - ERP KW - mismatch negativity KW - MMN KW - P3 KW - perception KW - working memory KW - WM KW - relevance TI - Mismatch negativity (MMN) is altered by directing attention SP - 1187 AV - public EP - 1190 ER -