Event-related potentials as asymmetry indices of lateralized cognitive processes during music and verbal tasks

The present study replicates and extends earlier findings by using event-related potentials (ERPs) as a means of providing information about differential hemispheric engagement in cognitive processing. ERPs were recorded from T3, T4, T5 and T6 in response to task-irrelevant tone pips superimposed on white noise, on music and on verbal passages, which are thought to differentially activate the two hemispheres. The latencies and amplitudes of three peaks (N1, P2 and N2) were obtained in 37 women. Task-related ERP asymmetries were found only for the peak amplitude of N2 recorded at posterior-temporal scalp areas, whereas at the anterior-temporal recording, there were no interactional effects. The hemisphere assumed to be most engaged in task processing showed a smaller N2 peak amplitude to tone pips at the posterior-temporal scalp area than the hypothesized unengaged hemisphere. A result common to the three peaks in the ERP was that peak latencies were longer in the music than in the noise condition. Finally, the posterior-temporal areas produced longer N2 peak latencies in verbal and even more in music conditions compared to white noise conditions. No differences in latencies were found between hemispheres during the ongoing cognitive tasks.