on the standardized Seashore Test.^65 The stimuli on the tempo and meter trials were modeled
on the Gordon Musical Aptitude Profile.^66 These stimulus materials were adjusted (i.e. in
tempo or accentuation) so that the stimuli on the tempo, phrasing, duration, meter, and pitch
control trials were as similar as possible. Different conditions varied with respect to the exact
nature of the task being performed, with stimuli being in almost all respects constant across
conditions. Although tempo, pattern, and meter stimuli had more tones per sequence,
between 9 and 12 events, approximately the same total number of tones per scanned interval
were presented in the duration task as in the tempo, pattern, and meter tasks. A ‘different’ trial
contained the same number of events (and accents) and was of the same total duration as the
‘same’ trials (by playing them at different tempi), except in the duration condition. In
the pitch task, the tone alternated between 415, 440, and 466 Hz in sequences of 12 462-ms
(quarter note) tones, without rests. Across all conditions, the intersequence interval was
1000 ms, and the intertrial interval was 1750 ms; the trial time was 14 s on average.
Stimuli were adjusted to produce comparable mean accuracy of musicians and of non-
musicians on each task. Each subject subsequently performed 11 PET trials: two trials each
of the pattern task, duration task, meter task, tempo task, and pitch control task, as well as
one rest trial. The subject’s eyes were closed on all trials. During each 60 s of task there were
four covert discrimination judgments. For half of the trials, the pair of stimuli was ident-
ical. After the PET session, subjects replicated the trials from the PET session, overtly indi-
cating their responses. Their average performance across the latter trials confirmed that
task difficulty was equated across conditions and across groups.
To highlight some of our principal findings, for both nonmusicians and musicians, dis-
tinct patterns of brain activity were detected for the discrimination of pitch and each
musical rhythm. There were also distinct differences between nonmusicians and musicians
during each discrimination.
For pitch (contrasted with rest), superior temporal areas (BA 21/22) were activated on
the right in nonmusicians and on the left in musicians (Figure 17.7A and D). However,
middle and inferior temporal areas (BA 21/20) were activated on the right in both groups
(Figure 17.7B and E). These temporal activations confirm prior neurological and neuro-
imaging studies, including those for the comprehension of melody above.6,7,11,34–36
There were also strong cerebellar activations during pitch (Figure 17.7C and F), again
confirming our earlier PET data. The cerebellar activations are not likely related to motor
activity since no overt motor activity occurred and there was little or no activity detected
in neocortical motor areas. Instead, the cerebellar activity seems to support perceptual or
cognitive processing of pitch (or melody). Interestingly, the nonmusicians showed strong
predominantly left-sided activation in posterior lateral cerebellar hemispheres (Figure
17.7C). The left cerebellum projects to the right cerebral cortex, so the activation in left
cerebellum is likely supporting the right temporal activation for pitch. However, musicians
showed bilateral cerebellar activation (Figure 17.7F), apparently supporting bilateral tem-
poral activation.
The key rhythm-specific activations were as follows. First, certain activations were
generally present for each rhythm task and for both nonmusicians and musicians, such as
basal ganglia and cingulate cortex. The cingulate activations are likely involved in attention
functions required in the task.67–70
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