When Music Stops Making Sense
manuelm...@gmail.com
most of us take for granted the smoothness with which the flow of
events blends together. Our brains stitch together what might
otherwise seem to be a disjointed sequence of individual events into a
coherent stream of information about the world around us. Language is
an obvious example, of course, as letters are bound together into
words, words are grouped into phrases and sentences, and sentences
form paragraphs and discourse. But music, too, relies on our ability
to bind together smaller elements into larger structures. Individual
notes are strung together to form melodic motifs. Melodic motifs are
used to shape phrases, which in turn form songs or even movements of
symphonies. Notes sung simultaneously by different voices or played by
different instruments are combined to create harmonies. How our brains
bind together these discrete pieces of auditory information to create
the experiences of hearing, remembering, or performing music is at the
heart of a recent surge of neuroscience research aimed at
understanding this ubiquitous human phenomenon.
Despite music's central role in human cultures around the world, and
its potential to help unlock the mechanistic secrets of the brain, its
arrival on the scientific scene is rather recent. Nonetheless,
exploring music's basis in the brain can help shed light on a
remarkable human activity that has been a part of our social and
cultural fabric for millennia. Moreover, while the relegation of music
to scientific second fiddle is understandable, we should not minimize
the role that music can play in our broader understanding of how the
brain works.
Translating a Musical Score into Action
Understanding how the brain accomplishes music is likely to enhance
our understanding of the brain's inner workings for the simple reason
that musical behaviors include the same elements of perception,
action, emotion, and other mental operations as so many other kinds of
behavior. To get a handle on how music might be processed by the
brain, scientists use two primary methods: case studies of people who
have suffered some form of brain damage and neuroimaging studies to
measure physiological changes in the brains of healthy people while
they perform various tasks related to music, such as remembering short
melodies or reproducing rhythms. Studying people with an injury to the
brain provides a particularly fascinating window into the workings of
the brain because it helps researchers understand general principles
of brain organization while taking into account variations in
individual cases.
Following damage to the brain, such as the death of tissue after a
stroke, a person is likely to experience deficits-whether in
perception, movement, attention, or memory-that make performing
previously routine behaviors and tasks more difficult. If
neurologists carefully identify these deficits, they can pinpoint the
specific mental operations that are impaired. When multiple patients
who have damage to the same brain area experience the same deficits,
the neurologist can ascribe the underlying mental operations to
specific brain areas. For example, damage to the left side of the
frontal lobe of the brain in a region known as Broca's area results in
Broca's aphasia, the inability to produce sequences of speech sounds
and words.
Closer scrutiny of individual patients presents a more intriguing
picture, however. Often some highly specific functions are lost but
others are spared, despite the brain damage being widespread or
occurring in a region commonly associated with a multitude of
functions. My launching point for exploring music in the brain in this
article is the remarkable personal account of one such patient, Ian
McDonald, M.D.1
McDonald was a British neurologist with an avocation as a classical
pianist. He was a skilled musician who spent much time playing the
piano, both alone and in small chamber music groups. But as a result
of a stroke in 2004, he lost his ability to read and play music from a
score, as well as to appreciate it on an emotional level.
Fortunately, he documented both his symptoms and his recovery. His
report, taken together with other similar case studies, provides
insight into the role that the brain's parietal lobes play in
transforming information from one form into another and in binding
together the stream of events into a continuum of meaningful
experience.