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>Reply-To: "Rafael O. Quezada" <abacus.roqATprodigy.net>
>From: "Rafael O. Quezada" <abacus.roqATprodigy.net>
>Subject: pho: Exploring the Musical Brain-Scientific American
>Date: Sun, 4 Feb 2001 09:41:17 -0800
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>Exploring the Musical Brain
>Music may be even more ancient than the human race, over which it
>holds tremendous sway. Scientists are beginning to find out why.
>It can bring us to tears or to our feet, drive us into battle or lull us
>to sleep. Music is indeed remarkable in its power over all humankind.
>Perhaps for that very reason, no human culture on earth has ever lived
>without it: people making music predates agriculture and perhaps even
>language. Take, for instance, the recent discoveries in France and
>Slovenia of surprisingly sophisticated, sweet-sounding flutes, made by
>our Neanderthal cousins. Some of these instruments, carved from animal
>bones, are as much as 53,000 years old more than twice as old as the
>famed cave paintings in Lascaux.
>Despite the ancient and primal nature of music, though, scientists have
>struggled with some very fundamental questions about its origins and
>purpose. How does the brain process music? Are there special neural
>circuits dedicated to creating or interpreting it? If so, are they, like
>language, unique to human beings? Or do other animals possess true
>musical ability? Why is an appreciation for music practically universal?
>Has it conveyed some evolutionary advantage through time? The field of
>biomusicology is still fairly young, but during the past few years, it
>has started to answer some of these questions.
>Perhaps most basic, researchers have discovered that music like language
>stimulates many areas in the brain, including regions normally involved
>in other kinds of thinking. For this reason, Mark Jude Tramo of the
>Harvard Medical School argues in a recent issue of Science that the brain
>doesn't have a specific "music center," as others have suggested. As an
>example, he points to the left planum temporale. This tiny brain region
>is critical to the golden musical gift of perfect pitch the rare ability
>to recognize by ear a perfect middle C hit on the piano, or the E of a
>passing car horn. But the left planum temporale also plays an important
>role in language processing. Thus, Tramo writes, there is "no grossly
>identifiable brain structure that works solely during music cognition.
>However, distinctive patterns of neural activity within the auditory
>cortex and other areas of the brain may imbue specificity to the
>processing of music."
>Some of the patterns Tramo talks about have revealed themselves through
>neuroimaging studies others through tests on patients that, like the
>subjects of Oliver Sacks's popular books, have suffered unusual forms of
>brain damage. In the late 1990s, for instance, Isabelle Peretz at the
>University of Montreal and Catherine Liégeois-Chauvel of INSERM in
>Marseilles ran several experiments on 65 people who, because of epilepsy,
>had had part of one or the other temporal lobe surgically removed. From
>these studies they concluded that musicality resided primarily on one
>side of the brain the right hemisphere.
>The experiments were simple: Peretz and Liégeois-Chauvel played different
>songs for each patient twice. Sometimes the melodies were exactly the
>same. Other times, they had changed in one of several attributes, which
>researchers describe as "dimensions": first among them is pitch, which
>pertains to the actual frequency of a particular tone; the second is
>rhythm, or the duration of series of notes; the third is tempo, the
>overall pace of a piece; the fourth is contour, which describes the shape
>of a melody, or its pattern of rises and falls in notes; the fifth is
>key, or the set of pitches to which notes in a melody belong; other
>dimensions include timbre, loudness and spatial location.
>The scientists found that people with damage to the left temporal lobe
>had difficulty recognizing changes only in key, whereas those with damage
>to the right side struggled to recognize changes in both key and contour.
>Later imaging studies showed a similar bias toward the right hemisphere
>particularly among nonmusicians although Tramo notes that more recent
>work calls some of this "musical hemisphere" hypothesis into question.
>"The belt and parabelt areas [of the auditory cortex] in the right
>hemisphere discriminate local changes in note duration and separation,"
>he writes, "whereas grouping by meter involves mostly anterior parabelt
>areas in both hemispheres."
>From Mind's Eye to Emotion's Seat
>For certain, it is becoming apparent that unexpected and unsophisticated
>areas of the brain are sometimes involved in interpreting, writing,
>feeling or performing music. As some research has showed, even the visual
>cortex sometimes gets into the act. Hervé Platel, Jean-Claude Baron and
>their colleagues at the University of Caen used positron emission
>tomography (PET) to monitor the effects of changes in pitch. What they
>found much to their surprise was that Brodmann's areas 18 and 19 in the
>visual cortex lit up. These areas are better known as the "mind's eye"
>because they are, in essence, our imagination's canvas. Any make-believe
>picture begins there. Thus, Baron suggests that the brain may create a
>symbolic image to help it decipher changes in pitch.
>But music goes much deeper than that below the outer layers of the
>auditory and visual cortex to the limbic system, which controls our
>emotions. The emotions generated there produce a number of well-known
>physiological responses. Sadness, for instance, automatically causes
>pulse to slow, blood pressure to rise, a drop in the skin's conductivity
>and a rise in temperature. Fear increases heart rate; happiness makes you
>breathe faster. By monitoring such physical reactions, Carol Krumhansl of
>Cornell University demonstrated that music directly elicits a range of
>emotions. Music with a quick tempo in a major key, she found, brought
>about all the physical changes associated with happiness in listeners. In
>contrast, a slow tempo and minor key led to sadness.
>Robert Zatorre and Anne Blood at McGill University corroborated
>Krumhansl's findings with PET imaging experiments. They created original
>melodies containing dissonant and consonant patterns of notes, and played
>them for a group of volunteers willing to be scanned at the same time. As
>expected, dissonance made areas of the limbic system linked to unpleasant
>emotions light up in the PET scans, whereas the consonant melodies
>stimulated limbic structures associated with pleasure.
>That music strikes such a chord with the limbic system an ancient part of
>our brain, evolutionarily speaking, and one that we share with much of
>the animal kingdom is no accident, some researchers assert. In another
>recent paper in Science, Patricia Gray, head of the Biomusic program at
>the National Academy of the Sciences, and several colleagues from around
>the country propose that music came into this world long before the human
>race ever did. "The fact that whale and human music have so much in
>common even though our evolutionary paths have not intersected for 60
>million years," they write, "suggests that music may predate humans that
>rather than being the inventors of music, we are latecomers to the
>Humpbacks, Hummingbirds and Human Composers
>Gray and company note that humpback composers employ many of the same
>tricks human songwriters do. In addition to using similar rhythms,
>humpbacks keep musical phrases to a few seconds, creating themes out of
>several phrases before singing the next one. Whale songs in general are
>no shorter than human ballads and no longer than symphony movements,
>perhaps because they have a similar attention span. Even though they can
>sing over a range of seven octaves, the whales typically sing in key,
>spreading adjacent notes no farther apart than a scale. They mix
>percussive and pure tones in pretty much the same ratios as human
>composers and follow their ABA form, in which a theme is presented,
>elaborated on and then revisited in a slightly modified form.
>Perhaps most amazing, humpback whale songs include repeating refrains that
>rhyme. Gray and her colleagues say that whales might use rhymes for
>exactly the same reasons we do: as devices to help them remember. As a
>recent study showed, whale songs are often rather catchy. When a few
>humpbacks from the Indian Ocean strayed into the Pacific, some of the
>whales they met there quickly changed their tunes singing the new
>whales' songs within three short years.
>Back on land, birds, too, make music much like people. "When birds compose
>songs they often use the same rhythmic variations, pitch relationships,
>permutations and combinations of notes as human composers," Gray and her
>colleagues write, citing work done by their late co-author Luis Baptista.
>"Thus, some bird songs resemble musical compositions; for example, the
>canyon wren's trill cascades down the musical scale lie the opening of
>Chopin's 'Revolutionary' Etude." That same bird sings in the chromatic
>scale, which divides the octave into 12 semitones, and the hermit thrush
>sings in the so-called pentatonic scale. It is perhaps because these
>birds pitch their songs to the same scale as Western music that people
>find them so attractive.
>Why would such different creatures with such different physical means for
>making sound all adopt such astonishingly uniform patterns for their
>melodies? Gray and her colleagues conclude that the similarities "tempt
>one to speculate that the platonic alternative may exist that there is a
>universal music awaiting discovery." But in fact, there is currently
>considerable debate over the purpose of music, and whether it was
>adaptive for humans in evolution or not.
>"Auditory Cheesecake" or Evolutionary Advantage?
>Linguist Steven Pinker of the Massachusetts Institute of Technology has
>proposed that music is merely "auditory cheesecake," or "an evolutionary
>accident piggy-backing on language," as Daniel J. Levitin at McGill
>University explained in a recent issue of the journal Cerebrum. But many
>scientists Levitin among them don't agree. "Some researchers are finding
>that listening to familiar music activates neural structures deep in the
>ancient primitive regions of the brain, the cerebellar vermis," Levitin
>writes. "For music so profoundly to affect this gateway to emotion, it
>must have some ancient and important function."
>Geoffrey Miller of University College London has proposed that musical
>ability like broad shoulders or showy plumes may serve to demonstrate
>fitness to a potential mate. After all, singing or playing an instrument
>well requires dexterity and good memory. Another suggestion Levitin makes
>is that music functions as communication, perhaps mimicking the rhythm
>and contour of our species' primitive calls. So, too, he proposes that
>perhaps music conveys an advantage through stimulating our primitive
>Most interesting, he suggests that music stimulates our drive to find
>patterns in the environment. "Our brain is constantly trying to make order
>out of disorder, and music is a fantastic pattern game for our higher
>cognitive centers," he writes. "From our culture, we learn (even if
>unconsciously) about musical structures, tones and other ways of
>understanding music as it unfolds over time; and our brains are exercised
>by extracting different patterns and groupings from music's performance."
>It is this very kind of pattern recognition which is extremely important
>for making sense of the world around us that Keith Devlin suggests in
>his book The Math Gene gave rise to language and stands behind
>mathematical ability as well. To be certain, researchers won't agree on
>the purpose of music anytime soon which fortunately shouldn't stop any
>of us from enjoying it. Kristin Leutwyler
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