Music and the Brain: A Primer

Damn, I love good research.

I came across a newly published study of people's emotional responses to music, noted that I recognized one of the authors (Robert Zatorre of McGill University) and was reminded of research a couple of years ago by 3/5 of the same authors.

Side note: I'm rather tempted to pursue academic study of music and the brain (I like to call it the budding field of neuromusicology) in Montréal, seeing as Zatorre is at McGill and co-directs the BRAMS International Labratory for Brain, Music, and Sound Research with another favorite researcher of mine, Isabelle Peretz at the Université de Montréal.

In my next post, I'm going to give overviews of the two studies mentioned above and discuss some thoughts about them.  First, however, I will give a citation-free, pistachio-sized nutshell of a primer on what is known about the relationship between music and the brain.

Primer

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The Ear and Temporal Lobes

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The experience of listening to music begins, of course, at the ear.  Tiny hair cells in the cochlea respond to fluid vibrations effected by the bones of the middle ear.  These bones respond physically to pressure; specifically, changes in air pressure (sound waves).

The Ear (with a really long canal).

Hair cells respond to different frequencies (which define pitch) and amplitudes (volume) and send a neurological signal into the brain — they make the transition between the physical and the chemical aspects of sonic transmission.

The Cochlea and Its Hair Cells

The signals sent by these cells are primarily directed to the temporal lobes of the brain.  The temporal lobes are known to interpret the signal information as frequency, amplitude, and duration, which together account for all audible variations in sound.

The Left Temporal Lobe

Cool, yes?  Well, this happens for all sound, be it music, speech, or sonic boom.  There must be other parts of the brain that interpret everything that makes music music.

The Frontal Lobe and Cerebellum

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The elements of music are more profound than the elements of sound; harmony, tempo, and melody must at least be included.  I'll get harmony out of the way first.  When discussed in terms of the relationship between simultaneous pitches, I am willing to simplify and chalk it up to the temporal lobes.  When discussed in terms of the underlying tonalities of music, consider it to be more in line with melody, discussed below.

If you've ever been caught up in the pounding *thump*thump*thump*thump* of loud club music, you probably don't need much convincing that tempo has a primitive, reptillian characteristic in our brains.  If you aren't so easily swayed, consider the beating of hearts.  The necessity to keep hearts pumping with tempo has been around in our evolutionary history much longer than the luxury of understanding melody (well beyond when we were reptiles).  If you still aren't convinced, bugger off, I'm trying to give a primer here!

The part of the brain responsible for keeping our heartbeat is the cerebellum, part of the "reptillian brain."

The Cerebellum

The same part of the brain that controls the beat of a heart plays a huge role in interpreting the beat of music (tempo).  I know you're shocked, but take a deep breath and we'll move on.

Melody is a complicated beast; without both pitch variation and rhythm it can't exist.  Melody is more of an abstract concept than previously discussed elements.  Whereas other items can be objectively measured, there is no unit of melody — no physical characteristic by which it can be defined.  Fortunately, we have brainstuff (can we please make that an official word, Webster's?) that is well-suited to the abstract.  Behold the frontal lobe:

This incredible region of the brain plays the largest role in conceptualizing the abstract.  In the case of musical melody, it's actually doubly suited, because it also conceptualizes the future, and therefore effects the feeling of anticipation.  Composers make their livings by toying with anticipation (or by selling insurance, but I'm trying to be positive).  Almost all music creates interest by defining a tonal home base and then straying from it; stringing the listener along until it returns with resolution.  The tried and true structure of western melody does exactly this (so does the underlying structure of harmony, hence their strong relationship).

Emotion and Memory

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I've heard rumor that when some people listen to music, they experience "emotions."  I know it sounds like gibberish, but there are parts of our brains that are measurably active when people experience "feelings," including the ones allegedly sparked by music.  Though emotional activity in the brain requires interactions between multiple regions, the primary one is the amygdala.

The Amygdala

Music can have the effect of inducing memory recall of items ranging from associated lyrics to an event in one's past.  The primary region of the brain involved in forming and recalling memories is the hippocampus.

The Hippocampus

Hippocampus is Greek for "seahorse."

Still to Learn

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So much.  In short, the questions that the soon-to-be-discussed research attempt to address are:

• How is emotion tied to the experience of enjoying music?
• What physiological or chemical cues can tell us more about how the brain interprets music?
• What is the role of anticipation in the brain when listening to music?

Feel free to ask questions!