How Biological Is Music?

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Music is a spiritual enigma. It can elevate us to the loftiest heights of ecstasy, unlock repressed memories in a heartbeat, or unleash a flood of emotion to leave us breathless. Research reveals that music has a similar effect in the realms of sex and food.

Here in Montreal, scientists are discovering how music acts in the brain to stir our souls. How does music tug heartstrings in ways that words cannot? "The message of music and its ability to touch our emotions is more abstract than by language," said Ante Padjen, a musician and neuroscientist at McGill University. "Music exists within a cultural context and one musical piece can elicit different emotions from different cultural groups. Even within cultural groups each individual has a unique life experience that is drawn from when reacting to music."

The daunting challenge that neuroscientists face is to uncover how biology fits in among all these social variables. What biological rules persist despite the different cultural contexts in which music is appreciated?

Montreal scientists are not in full agreement about the nature of the quest. Is there a single music centre in the brain? Groundbreaking brain imaging studies suggest that several distinct brain areas are involved in the processing and appreciation of music. However, studies on musically impaired individuals also suggest that there may be some distinct specialized networks in the brain devoted specifically to music cognition.

Life without music for some

For example, some of the brain circuits involved in music perception appear to be separate from those that process language and other sounds in the environment. Evidence for this comes from studies on people with amusia, a severe form of tone-deafness. Amusical individuals are unable to perceive pitch differences in music, and consequently may have an inability to sing in tune, dance to music, or remember songs. Surprisingly, such individuals have otherwise fully normal cognitive abilities, and their language and hearing abilities are unscathed.

These studies also suggest that people must first perceive music normally in order to experience the joy of music. One amusical individual studied by Dr. Isabelle Peretz, a psychologist at the University of Montreal, could not detect pitch variations in music smaller than two semitones apart and reported that music sounded like noise and in fact induced stress.

Another study by the same author reported that amusical individuals were unable to identify wrong notes and musical dissonance. Most of those individuals also said that they did not appreciate music. Some found it so unpleasant that they tried to avoid it altogether.

Clearly a functional problem in the brain is involved in amusia. However, brain imaging studies on amusical individuals have not yet revealed any obvious anatomical differences from the brains of normal individuals.

Pleasures heard in Xanadu

Although the suspected damage in amusical individuals may be too fine to identify with current scientific imaging techniques, other imaging studies such as those conducted in Montreal have led to some spectacular discoveries about emotional responses to music.

One such study, performed by scientists at McGill University, showed for the first time that music activates the same reward or pleasure centres in the brain that respond to the pleasures associated with eating and sex.

The study is significant because it suggests music is as important to us as biologically relevant survival stimuli. "Although we can theoretically live and procreate without the ability to appreciate music, it seems important as far as our happiness and well-being is concerned," said Anne Blood, a co-author of the study, who is now at the Massachusetts General Hospital.

The study found that only music beautiful enough to consistently elicit the highly euphoric experience of chills or "shivers-down-the-spine" activated reward centres that are popularly recognized as pleasure centres of the brain.

These reward centres are part of a highly complex system that includes constellations of cells organized into functional precincts. The system is responsible for the natural pleasures associated with taste, sex, and warmth, for example. Such natural rewards lead to reinforcement or repetition of behaviour.

Although all pleasurable experiences seem to feed into a common reward system, the system has the power to discriminate and does not respond equally to all. The system may also be able to discriminate between different types of music, explaining why not all musical pleasures are equal, either intrapersonally or interpersonally.

Neurotransmitters deliver both the music and the high

Scientific studies have identified these pleasure centres by using psychically active chemicals and electrical stimulation. They have revealed that the nerve pathways require a neurotransmitter called dopamine. The action of this chemical seems critical in mediating responses that we perceive as rewarding, and it probably plays a key role in generating feelings of euphoria. Thus a blissful music experience quite likely has a chemical basis in the dopamine molecule.

The discrimination of musical sounds takes place in a recently evolved brain region called the auditory cortex, which is responsible for integrating and responding to a musical piece and deciding whether or not it is spiritually inspiring. However, musical information is processed in many other areas of the brain before it reaches the auditory cortex. Relatively primitive brain areas that regulate movement and memory may also contribute to our emotional response provoked by music. After various consultations, the brain makes a decision that leads us to dance, tap our fingers, grimace, or smile in appreciation. Interestingly, research shows that while we listen to music, motor areas of the brain also become active even if we don't initiate movement.

Singing as evolutionary anthem

Scientists are undecided on why such a refined system for music processing has evolved in humans or in other animals, for that matter. According to Blood, song may have evolved out of the language phenomenon called prosody, or the changing of tones in our speech when asking a question or making a statement. Other scientists, such as Dr. Sandra Trehub from University of Toronto, think it may have evolved out of attempts to soothe infants with non-verbal sounds.

Whatever the case, the discovery of Neanderthal flutes in Europe suggests that a "music instinct" has been developing within us for thousands of years. In the words of Ian Cross, a music psychologist at the University of Cambridge, "Without music, it could be that we would never have become human."