Event-related potentials in musically sophisticated and unsophisticated subjects: A study on hemispheric specialization

Event-related potentials (ERPs) to tone pips were elicited while 14 musically sophisticated and 37 unsophisticated women were engaged in the several conditions. Subjects were asked to detect a series of low-tone pips, "key" words, and musical themes during Noise, Verbal and Music conditions, respectively. ERPs were recorded from T3, T4, T5 and T6 temporal scalp sites, referred to linked mastoids. ERPs were elicited in response to the second of a pair of task-irrelevant tone pips under each condition. In the Verbal condition both groups of subjects showed smaller N2 peak amplitude in the left posterior-temporal recordings with respect to the right. In the Music condition, naïve subjects exhibited the opposite hemispheric trends, while sophisticated subjects did not. For sophisticated subjects the P2 peak latency was longer in the left hemisphere during Verbal condition, and in the right during Music condition; for unsophisticated subjects P2 peak latency was not different in the two hemispheres. The anterior scalp recordings did not show hemispheric asymmetries. The data support the assumption that N2 amplitude may reflect hemispheric asymmetry for naïve subjects. For sophisticated subjects this variable showed a left hemispheric engagement in the Verbal condition and no hemispheric differences in the others. This lacking result was attributed to the lower task difficulty experienced by these subjects in the processing of musical material