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Neuropsychology refers to the study of how mental functions arise from the brain, and has a long and rich history at the MNI. Among the traditional topics of neuropsychological study—memory, language, perception, attention, planning, emotion—one does not usually encounter music. Indeed, I have sometimes been asked to justify why our laboratory focuses on music (the subtext to this question being that it seems like a frivolous pursuit). Yet, a moment’s thought will suffice to realize that even a simple musical task (say, hearing a melody and singing it back)  requires all of the above-mentioned mental functions, and then some. You need to attend to and perceive the tones in the melody, these need to be relayed to a memory system for recogntion, followed by planning and sequencing of the motor articulators for singing, and so forth. The ease with which even a small child can easily accomplish this feat, belies the complexity of the processes involved. So the reason we study music is because it offers us a unique and powerful window onto the human brain’s most remarkable abilities, a view that would not necessarily be found through more traditional avenues.

An example drawn from our recent work may help to illustrate this point. Almost everyone has noticed a strong feeling of wanting to move (sway our body, tap our feet, snap our fingers) when listening to music. Why should this be? My fomer graduate student, Joyce Chen, now at Oxford, and my colleague Virginia Penhune from Concordia University, and I set out to explore this question. We devised a series of experiments in which listeners were asked to listen to and tap out rhyhtmic sequences while they had their brain activity measured via functional MRI scanning. The basic findings were that there is a close and subtle interplay between the sensory part of the brain that interprets signals (the auditory cortex) and various components of the motor system that prepares, sequences, and plans movements (the premotor and supplementary motor cortices). Perhaps the most surprising result was that motor-related areas, which are conventionally thought to be involved only when there is actual movement, are active when structured rhythms are presented even if the listener is not moving at all. This implies that the auditory and motor systems are tightly coupled, and provides an explanation for the phenomenon of moving in time to a musical beat.

One might still legitimately ask what good this knowledge is. Well, one potential application is in the area of motor rehabilitation. It has been known for some time that patients with movement disorders such as Parkinson’s or stroke, can learn to walk more effectively with a musical soundtrack; but until now the reason why this seems to work was unknown. Our research offers a glimpse at the underlying mechanism of this motor entrainment which is essential if such therapies are to move from a curiosity to a more structured and systematic approach.

On a more global basis, this research offers two lessons. First, that studying musical processing can be enlightening about brain function in ways which would not otherwise be possible (for instance, speech does not have the same rhythmic structure as music and does not elicit these effects; similarly, visual inputs do not produce the same motor entrainment. Second, this set of studies and many others demonstrate once again the value of basic, curiosity-driven research. By asking the “why?” question we achieve much more fundamental insights than any specific applied question would yield.

For further reading:

Chen, J.L., Penhune, V.B., and Zatorre, R.J. (2006) Interactions between
auditory and dorsal premotor cortex during synchronization to musical
rhythms. Neuroimage,32, 1771-1781.

Chen, J.L., Zatorre, R.J., and Penhune, V.B. (2008) Moving on time: brain
network for auditory-motor synchronization is modulated by rhythm
complexity and musicaltraining. Journal of Cognitive Neuroscience,
20, 226-239.

Chen, J.L., Penhune, V.B., and Zatorre, R.J. (2008) Listening to musical
rhythms recruits motor regions of the brain.
Cerebral Cortex, 18, 2844-2854.

Zatorre, R.J., Chen, J.L., and Penhune, V.B. (2007) When the brain plays
music. Auditory-motor interactions in music perception and production.
Nature Reviews Neuroscience, 8, 547-558