cortex, the cerebellum and the posterior perisylvian regions. In addition, this study showed
differences in gray matter concentrations in regions not expected to show differences, such
as the posterior superior parietal cortex. The superior parietal cortex does play an import-
ant role in music performance, since it may serve as an integrator of visual and auditory
information with motor planning activities. Its importance in musical sight-reading has
already been shown.^55
Functional brain differences between musicians and nonmusicians
Most pronounced functional differences between musicians and nonmusicians have been
found in perisylvian brain regions with various perceptual tasks ranging from listening to
musical pieces, pitch discrimination and memory, harmony, melody, and rhythm
tasks.^4 – 6,11,56,57It appears from these studies that musicians and nonmusicians process
music in a different way, leading to more left hemispheric activation with increased musi-
cal sophistication. The reason for this is unclear and the historic explanation of a more
emotional or holistic approach to music by the nonmusician vs a more analytic approach
to music by the trained musician is an oversimplification of the underlying processes.
However, music is certainly not just a right or left hemisphere issue. There may be aspects
of music that will be processed more on the right hemisphere by both musicians and non-
musicians (e.g. melodic contour tasks) while there are others that will be more processed
on the left by both groups (e.g. rhythmic tasks). Of interest are of course those aspects of
music that may be processed differently. One example for this may be the processing of
pitch information.
A region that seems to play an important role in the processing of musical stimuli is the
posterior perisylvian region. This region is known to be very asymmetric in normal right-
handers. The planum temporale has long been used as a marker of this asymmetry and in
general as a marker of cerebral dominance, at least for language and handedness.^58 It has
been found that the majority of right-handers have a leftward planum temporale asym-
metry whereas the majority of left-handers have either a symmetric planum temporale or
show a rightward asymmetry. The planum temporale is not only a structural marker of
left-hemispheric dominance for language, it is also involved in auditory processing and as
such is of great interest for studies investigating laterality effects of auditory processing.
Recent studies have found associations between PT surface area and functional dominance
when listening to stories^59 and the PT has been found to be activated in various musical
tasks.^60 – 64,57
In an anatomical MRI study designed to test the hypothesis that musicians might have a
different degree of hemispheric dominance than nonmusicians, we found that musicians
differed significantly from nonmusicians by having an increased leftsided asymmetry of
the planum temporale (Figure 24.6). The surprising finding was that a subgroup of musi-
cians, those with absolute pitch, explained all the difference between the musician and non-
musician group. The absolute pitch musician subgroup showed an increased leftsided
asymmetry of the planum temporale.^9 Absolute pitch is the ability to identify a tone in the
absence of a reference tone. The incidence varies between different studies, but is presumed to
be between 5 and 20 per cent among musicians. In a subsequent study, Keenan et al.^13 compared
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