Visual mismatch negativity elicited by magnocellular system activation.

The processing of visual motion was tested by means of event related potentials recording (ERP) using a paradigm designed to produce a visual mismatch negativity effect. The stimuli were unattended and presented in the peripheral visual field (outside the central 15 degrees). The standard stimulus consisted of an up/down motion sequence, whilst the deviant stimulus of a down/up motion sequence. Significant ERP differences between the standard and deviant conditions were found in 8 out of 10 adult subjects already in 80 ms and prevailingly in interval 145-260 ms from the initial stimulus presentation. The results demonstrate that the magnocellular information undergoes processing capable of detecting differences in the sequence of unattended peripheral motion stimuli.