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Fig. 7. Degradation in brainstem responses is common when the stimulus is embed- ded in background noise. While musicians’ and non-musicians’ responses are similar in quiet (top), the degradation of response morphology in noise (bottom) is mini-
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mized in musicians (red). Modified from Parbery-Clark et al., 2009.
undifferentiated phenomenon with little relationship to the
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these changes occur.
The behavioral, cognitive, cortical, and subcortical
advantages bestowed by musical training, serve to promote musical training as a logical strategy for improving basic sound transcription via the reinforcement of reciprocal sub- cortical-cortical processing interactions brought about, at least in part, by the strengthening of auditory memory and attention. This improved sound transcription, in turn, is a building block of phonological processing, reading, and the extraction of speech from background noise. Further work also can address the extent to which musical practice may serve as protection and remediation against hearing-loss or age-induced communication difficulties and a means to engender the formation of sound-to-meaning relationships
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a We are using the terms pitch, timing and harmonics as short- hand throughout this report. We recognize that these constructs have other strict meanings, and that such a tidy differentiation among these three constructs in speech and music is an over- simplification. For our purposes, we refer to pitch as the funda- mental frequency (f0) of a note or an utterance. In speech, f0 is a
This gives the researcher a technique to look for selective enhancements or impairments that is unavail- able in the more abstract realms of cortical physiology and imaging. The brainstem provides an exciting window into the sensory-cognitive reorganization that underpins the changes brought about by engagement with music. With it comes the promise of disambiguating the mechanisms through which
evoking sound.
The brain- stem response can serve as a potent efficacy measure of music-based education due to its fidelity to the stimulus, its individual-subject reliability, its experience-dependent mal- leability and its selective nature. Supported by National Science Foundation grants SBE-0842376 and BCS-092275. AT
End notes
that are so critical to human communication.
ms) segment and a complex non-harmonic (145–212 ms) segment, reveals an interesting pattern. Musicians’ responses to the earlier segment are smaller than nonmusicians’, while their responses to the later, complex, segment are larger (Fig. 8). This combination of processing strategies—both response efficiency and enhancement—to different types of acoustic stimulation has certain parallels to cortical studies in which musicians show an economy of response to harmonically simple sounds.136 In contrast, the musician’s enhancement to the more complex portion of the baby cry is in line with some of the other processing enhancements we have seen in musi- cians’ auditory brainstems. The results of this investigation demonstrate that subcortical processing differences in musi- cians extend toward non-musical and non-speech vocal sounds.
Summary and conclusions
As we learn more about the auditory brainstem response to speech and musical sounds, one of
the more interesting findings is that the
same neural processes that are dimin-
ished in poor readers and individuals
with difficulty hearing in noise are the
same processes that are enhanced in
musicians. Neither the deficits nor the
enhancements are pan-response. In
every case, with peripheral hearing as a
strict control, only subtle response
characteristics are affected while gross
morphology is maintained. This speaks
to the value of the brainstem response
in the investigation of possible neural
origins for reading and SIN perception
problems and musical-experience-
mediated processing advantages. Not
only is the response powerful because
of its suitability as an individual-sub-
ject probe, but it is many-faceted. That
is, its components—each tied inextri-
cably to components of the auditory
landscape—are separable; it is not an
Fig. 8. Musicianship extends to brainstem processing advantages to non-linguistic vocal sounds. The selective
nature of music training’s impact on processing is revealed within the response to a single baby’s cry (top). A com-
plex region of the musician’s response (red) is enhanced; a periodic part is reduced. From Strait et al., 2009.
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Musician’s Auditory World 21