Ly. Deouell et al., MISMATCH NEGATIVITY IN DICHOTIC-LISTENING - EVIDENCE FOR INTERHEMISPHERIC DIFFERENCES AND MULTIPLE GENERATORS, Psychophysiology, 35(4), 1998, pp. 355-365
The characteristics of mismatch negativity (MMN) elicited by dichotic
stimulation were examined using frequency-deviant stimuli presented to
the right, to the left, or to both sides. The experiment was run twic
e, once using earphones and once using loudspeakers in free field. Wit
h both modes of stimulation, deviants presented in the left, right, or
both ears, or tones that were switched between ears, elicited compara
ble MMNs, with a peak latency of about 180 ms. With earphones, the amp
litude of the MMN was bigger at the frontal-lateral right hemisphere s
ites than at the homologous left-hemisphere sites for all deviance con
ditions. Scalp current density analysis revealed that deviance in the
right side elicited bilaterally equivalent frontal current sinks and a
trend towards stronger contralateral current sources at the mastoid s
ites. In contrast, left side deviance elicited frontal sinks and tempo
ral current sources stronger over the right hemiscalp. These results a
re compatible with the multiple-generator model of MMN. The attention-
related role of the MMN is discussed, suggesting comparable attention
mechanisms for vision and audition.