303changes exists but is activated only during attentive listening. Whether we here evidence an
effect of differential training on brain plasticity or a result of appropriately chosen musical
instrument, remains unresolved on the basis of the present evidence. However, recent evi-
dence obtained by using both structural and functional methods of cognitive neuroscience
promotes the importance of training in reorganizing the brain functions.61,67,68
Temporal encoding
Very recently, also temporal domain of sound processing has attracted attention in
musician–nonmusician comparisons in MMN paradigm. This is valuable especially if the
temporal accuracy of the event-related potentials is taken into account—it allows one to
track the processing of very minute changes also in temporally complex sound sequences.
The first study investigated the accuracy of musicians vs nonmusicians to preattentively
encode regularity in relatively fast sound presentation rate and to react to infrequent sound
omissions in that sound stream.^69 In separate conditions, the sinusoidal sounds of 50 ms
were delivered every 100, 120, 180, and 220 ms to the subjects who concentrated on a read-
ing task. 15 musicians and 15 subjects without any formal training in music were
employed. Sound omissions occurred with the probability of 3 per cent. It was found that
while the sound omissions evoked the MMN in musicians in all conditions, in nonmusi-
cians the MMN was present only with two shortest stimulation rates. This suggests that
musicians have a prolonged window of sound integration.^70 Furthermore, the results of the
second experiment of these authors suggest that the temporal processing of musicians
within this window is also more accurate than in nonmusicians. In that study, musicians
and nonmusicians were presented with tone pairs. In the standard pair, the sound onsets
were separated by 150 ms whereas in the deviant pairs, they were separated by 100 or
120 ms. It was found that the MMN was elicited in musicians by both deviant pairs but in
nonmusicians only by 100 ms pair.
The second set of related experiments investigated the accuracy and efficacy of musi-
cians vs nonmusicians to preattentively encode sound sequences up to 1.5 s and to detect
violations in the regularities established by the sequences.^71 In the first of these experi-
ments, the sound sequences were either 750 ms or 1.5 s in duration (in separate condi-
tions). Four tones, ascending in pitch, were presented in a looped manner. The deviant
sequence consisted offive tones, thus being one tone longer than the standard sequence.
The MMN elicitation implied that musicians were able to encode the length and frequency
content of such a subsequence with both sequence durations. In contrast, in nonmusicians,
no MMN was elicited. In the second experiment, the standard sound sequences were also
either 750 ms or 1.5 s in duration but were made very simple in their pitch structure: they
consisted of four repetitions of the same pitch. After four tones, the pitch of all of them was
changed. Also here, the deviant sequences were one tone longer. It was found that the
MMN was elicited by the tone sequence lengthening in both subject groups with 750 ms
sequences and in musicians also with 1.5 s sequences. These data suggest that grouping of
sequential sounds can take place on a preattentive processing level irrespective of musical
skill with moderate sequence durations, but that professional musicians have more
advanced preattentive ability to group sequential sounds than nonmusicians when
sequences are lengthy. In other words, in its simple forms, auditory grouping does not
differ between subjects with different levels of expertise. However, with more complicated