362
is easier during childhood not only because our motor abilities are more malleable during
these early phases, but also because our auditory cortex has sensitive periods for self-organ-
ization. This does not mean that we cannot acquire these abilities any longer later in life,
but an equivalent outcome will require greater effort. Similar sensitive periods apply to lan-
guage learning: Learning a second language after the age of eight is definitely still possible,
but a foreign accent will usually remain.^43 Again, this effect may have its ultimate cause in
a decreasing malleability with age of recipient auditory cortical structures for auditory per-
ception and discrimination.^44
Conclusions
The connection between brain activation and musical perception is becoming clearer as
more and more refined techniques become available to image neural activity. Brain imag-
ing can be performed while subjects are listening to music or imagining it. One can meas-
ure the immediate correlates of music as well as its effects on brain development and later
brain organization. And, although animals do not have music (just as, in a strict sense, they
do not speak), one can still get a grasp of the exact neural mechanisms of music perception
by measuring the responses of single neurons in animal studies to various types of com-
plex sounds. An analysis, for instance, of how sound sequences are processed and stored by
neural networks would go a long way towards understanding the neural basis of music per-
ception. Other aspects, such as timbre and rhythm perception, could equally be tackled by
simpler paradigms in animal models.
Cortical plasticity has to be considered in at least two ways in the context of studies on
music and the brain. First, early experience with the world of sound will inevitably shape
our brain in an indelible fashion. Enhanced experience with sound, as it occurs with
musical training and, inevitably, in blind individuals, can profoundly alter the circuitry of
the part of the brain that processes complex sounds in general and music in particular. As
we experience these brain changes resulting from cortical plasticity from studies in both
humans and animals, we learn to appreciate how expanded areas of the brain lead to
enhanced perceptual abilities in the corresponding senses.
Acknowledgements
Supported in part by a grant from the National Institute of Deafness and Other
Communication Disorders (R01-DC03489).
References
1.Schlaug, G., L. Jäncke, Y. Huang, and H. Steinmetz(1995) In vivo evidence of structural brain
asymmetry in musicians.Science267, 699–701.
2.Pantev, C., R. Oostenveld, A. Engelien, B. Ross, L. E. Roberts, and M. Hoke(1998) Increased audi-
tory cortical representation in musicians.Nature392, 811–14.