This study examined differences in the spontaneous electroencephalographic (EEG) signal in terms of music training and gender. Coherence estimates obtained by spectral analysis provided an efficacious method to study these differences. In the first study, differences in the spontaneous EEG between subjects with and without music training were observed. Subjects with music training exhibited significantly higher coherence values both within and between cerebral hemispheres when compared with subjects without music training. The most striking differences were observed in the two lowest (delta and theta) and two highest (beta 1 and beta 2) bands, with differences in the temporoparietal regions of both hemispheres being most prominent. The findings are discussed in terms of specialized organization of brain activity that influences cortical connectivity. Using the same method, differences in spontaneous EEG were also found between male and female subjects. Females tended to have significantly higher interhemispheric coherence values when compared with males. Both findings are also supported by recently discovered anatomic differences.
This study was performed to test the usefulness of the EEG as a research instrument for music psychology in individuals. Measuring the degree of functional interrelatedness of brain areas by coherence estimates has turned out to be more efficient than amplitude mapping. Therefore, the method, based on the analysis of EEG periods of at least 1 min, has been expanded to estimate all possible coherence values between the 19 electrodes (i.e., 171 values) and to observe any significant changes in those values caused by different musical tasks. This report concerns observations in a total of 49 healthy subjects (29 male and 20 female). The main goal of this study was to determine the degree of engagement of either hemisphere in the processing of music. Two items were shown to indicate hemispheric involvement: (1) the topographic distribution of "focal points of coherence" (brain areas participating in coherence changes with respect to a great number of other brain areas) and (2) the number of intrahemispheric coherence increases. In most cases, both items seem to focus on the same hemisphere. Taking these as parameters for hemispheric engagement, the following principal observations were made: the beta bands (and particularly their uppermost ranges) seem to play a major role in the processing of music; the hemispheric engagement, however, need not be the same for each frequency band. No hemisphere seems to be preferred. When listening to music is shifted between different styles, laterality may change. When the same tasks are repeated at several weeks' intervals, a fairly large degree of consistency is found. Imagining music and composing clearly differs from listening by activating many more coherence increases in the beta band and by an increasing percentage of hemispheric interaction. This kind of analysis may also provide some clues as to how a piece of music is processed by an individual. The coherence changes observed may represent events taking place in a system of differential attention that selects and orders the sensory inputs before the musical material is further processed at higher order hierarchical levels.