ABSTRACT
The magnetoencephalographic (MEG) methodology has been applied in research of brain mechanisms of attention. Most of the studies have addressed the persistent issue of the possible selective-attention enhancement of the exogenous N1 in audition—in this case, its supratemporal component visible to the MEG. MEG studies have also tried to clarify the issue of the attentional sensitivity/insensitivity of Mismatch Negativity (MMN), the advantage being that N2b usually overlapping MMN in electrical recordings is not visible in the MEG. Lloyd Kaufman and Samuel Williamson and S. Curtis, Kaufman, and Williamson were the first to report MEG responses during selective attention. These authors interpreted their results, obtained with dichotic stimuli delivered at a fast rate, as evidence for an attentional modulation of the exogenous N1 and P2 components. E. Kaukoranta investigated MEG responses to duration decrements and O. V. Lounasmaa to intensity decrements. Both studies found a very similar MMNm under target-discrimination providing evidence for attentional insensitivity of MMN in the oddball paradigm.
