Electrophysiological correlates of verbal and tonal working memory.

The present study's basic research question concerns differences in the processing of verbal and tonal stimuli in working memory. Participants had to rehearse sequences containing tonal and verbal information and to decide whether a subsequently presented probe stimulus belonged to the previously presented sequence. Electrophysiological measures were taken and analysed with regard to local (event-related potentials, ERP) and global (microstates) aspects. A larger N400 amplitude occurred for new compared to old items in the verbal, but not the tonal condition. The microstate analysis revealed differences in the specificity of several microstates for old compared to new items in the tonal and the verbal working memory condition. Corroborating previous results, the present study reveals differences in the efficiency of working memory processes for tonal compared to verbal stimuli with processes being more capable for the verbal compared to the tonal condition.