ERPs associated with pitch discrimination

Besson et al. (2007) report a series of experiments showing that musical expertise enhances pitch discrimination. By musical expertise, their studies refer to the explicit musical training that differentiates musicians and non-musicians, contrary to the implicit musical expertise that constitutes implicit tonal knowledge, and that will be investigated in the present study. Their musical material consisted of tone sequences, half of which had their final tone increased in pitch by either 1/5 or ½ of a tone. Musician participants detected better the weaker pitch violations than non-musician, and this was reflected in an increased positivity to weaker pitch in musicians only (Schön, Magne, & Besson, 2004). In addition, Besson et al. (2007) report that six months of musical training made non-musician 8-year-old children more sensitive to weaker pitch deviations and this acquired sensitivity was associated with an enhancement of N300 and P600 components.

Musical expertise was also found to modulate pitch discrimination when stimuli were ignored, in an oddball experiment by Koelsch, Schröger and Tervaniemi (1999). The sequences consisted of a frequent major chord and of an infrequent chord that differed from the frequent chord by its middle tone, which was slightly lowered in pitch. Participants had either to detect the deviant stimuli (attentive condition) or to read a book and ignore the auditory stimuli (pre-attentive condition). Deviant chords elicited a MMN in musicians in both conditions whereas they elicited a MMN in non-musicians only in the attentive condition. This result indicates that the long-term training of professional musicians results in superior automatic processing of pitch, as revealed by the MMN elicited pre-attentively. Tervaniemi et al. (2005) intended to extend this result in an oddball experiment using tone sequences with three types of deviants: a small frequency deviant (.76% higher than the standard), a medium deviant (2.1% higher than the standard), and a large deviant (4.2% higher than the standard). Contrary to Koelsch et al. (1999), musical expertise did not influence the MMN component, which was elicited in both musicians and non-musicians by the three deviants, in both attentive and pre-attentive conditions. However, the N2b and the P3, elicited only in the attentive condition, were larger in musicians than in non-musicians. This result casts doubt on the pre-attentive influence of musical expertise but confirms its influence on pitch discrimination, at least at attentive levels.