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Sounds of the brain
“Before
you can be fitted with your Braincap, you have to be completely bald. …
A faint drumming sound accelerated until it became the lowest of audible
Cs, then raced up the musical scale until it disappeared beyond the range
of the human hearing… He presumed that his neuromuscular control was
being tested…” (3001 – The Final Odyssey, Arthur Clarke
1997).
- The Braincap, as described in Arthur C. Clarke’s science fiction
classic, 3001: The Final Odyssey, is the ultimate human-computer interface:
it connects the brain to a system that is able to read our thoughts and
upload new information. It is the educational machine of the third millennium,
where the wearer can acquire new skills in minutes that would otherwise
take years to master. As far as our current state of technology is concerned,
a system that uploads information into our brain cannot exist outside
the realm of science fiction. However, machines that can read our thoughts
are becoming present reality.
- Traditionally, electronic music is composed and played using controllers
that resemble standard musical instruments, such as piano-like keyboards.
In the past five years or so, there has been a growing interest in devising
new controllers for music. A number of innovative ideas have been proposed
and tested, ranging from video cameras that translate the movement of
body gestures into sound, to wearable musical controllers, such as gloves
that translate the movement of the hands into musical notes. However interesting,
these ideas still are based upon two conventional notions: stable control
and gesture. Such electronic instruments are stable in the sense that
they normally foster a one-to-one mapping between a physical controller
and a specific output. As in the case of traditional instruments, these
controllers often associate specific switches or sensors with the production
of definite sounds. Indeed, the notion that a certain key of the piano
must always produce the very same note makes the piano a very stable instrument.
Moreover, such controllers force musicians to rely upon physical gestures
to produce specific sounds. For example, a video camera-based controller
would produce a rising pitch if the performer moved his or her arm upwards,
and so forth. I am interested in challenging these notions by composing
music with systems that are unstable and non-gestural. To this end, I
built the Musical Braincap, an unstable and non-gestural musical instrument,
used for the first time in the premiere of Wegh, at The First Free International
Forum, in Bolognano, Italy, 2003.
- The electrical activity of masses of neurones acting in the human brain
produces electric fields that can be detected using electrodes placed
on the scalp, and measured using electroencephalogram technology (EEG).
My Musical Braincap uses EEG to track the electric field resulting from
the activity of the brain. This electrical activity is then converted
into information that can be used to control sound processing software
and digital synthesisers. In Wegh, the EEG information generated by my
brain during the performance of the piece, controlled software that manipulated
the spectrum of the sounds of the flute, played by Emanuel Dimas de Melo
Pimenta.
- Music calls upon widely dispersed areas of the brain, many of which
lie beyond our usual consciousness. Music is a profoundly integrating
activity: it requires the ability to recognise and imagine patterns of
sounds. Music requires sophisticated memory mechanisms, involving both
the conscious manipulation of concepts and subconscious access to millions
of networked neurological bonds.
- There are many examples in both musical and non-musical research fields
confirming that the EEG provides a rich source of information about our
musical thought processes. EEG technology has been particularly useful
for demonstrating that the brain expects sequences of stimuli that conform
to established circumstances. As a crude example, if you hear the sentence
"A musician composes the music", the electrical activity of
your brain will tend to run fairly steadily. But if you hear the sentence
"A musician composes the dog", the activity of your brain will
display significant electrical response immediately after the word "dog".
The human brain seems to respond similarly to musical events. Biomedical
technology allows scientists to look into our brains and see the specific
activity of the musical mind. My Neuroscience of Music research team at
the University of Plymouth in England is measuring musical brain activity,
using EEG scans that reveal the areas of the brain that experience or
create music.
- Composers develop different ways of bridging together verbal and non-verbal
experiences of the world. Whilst it is undoubtedly verbal language that
has allowed the human species to evolve culture and social conventions,
I believe that music has played an even more important role in our evolution.
- EEG signals can be categorised into four main components: a random-seeming
background; long-term coherent waves; short-term transient waves; and
complex ongoing waves. The random-seeming background, about which little
is known, is the residue observed after all known methods of waveform
decomposition are exhausted. Long-term coherent waves are commonly classified
according to their frequency into four bandwidths: Theta (4 – 7
Hertz), Alpha (8 – 12 Hertz), Beta (13 – 25 Hertz) and Gamma
(25 – 40 Hertz). They are often associated with certain states of
consciousness, such as alertness and sleep. Short-term transient waves
reflect neural activity associated with an external stimulus. Finally,
non-random complex components seem to exist emanating from the build up
of baseline activations from the vast neuronal masses within the brain.
This pattern is taken to be the result of the ongoing, self-organisation
of information during one’s experience of life. If these patterns
could successfully be measured, and sense made of them, we might witness
the mechanisms of higher level thought processes. Nobody has managed to
track these complex ongoing waves yet. The Musical Braincap focuses mainly
on long-term coherent waves because there is already a significant amount
of knowledge about them in the scientific literature, and the technology
for dealing with these signals is fairly well developed. Long-term coherent
waves can be measured with EEG technology, and it is possible to train
the brain to produce these frequencies using neurofeedback.
- We hear even within the womb, and we cannot shut our ears as we can
our eyes. All sound at all times has to be interpreted by our brains and
to do this we have evolved very complex neural systems. As early as six
months old, babies display highly developed abilities to recognise musical
structures. Music and language sound very similar early on because babies
simply hear the intonation of the voice. Newborn babies clearly respond
to particular voices and the tonal and rhythmic qualities of stories with
which they are familiar, suggesting that musical significance precedes
verbal.
- Neurofeedback is a form of biofeedback system. Any system that helps
us to monitor and/or control the functioning of the body can be regarded
as a biofeedback system. Biofeedback is often used for medical monitoring
purposes but it has also been used to increase the awareness of those
functions of our body that would normally be taken for granted, such as
variations in our body temperature or pulse rate. As an example, imagine
a biofeedback system composed of a thermometer and drugs for lowering
body temperature. The thermometer is used to read and analyse your body
temperature. If the temperature is higher than a specific threshold, then
you take the drugs to bring the temperature down; the effect of the drugs
can be monitored by taking your temperature again. An important aspect
of biofeedback is that the analysis of the information extracted from
our body can prompt us to take an action in order to achieve a certain
physiological goal. Analysis and action thus feed information back to
each other. Neurofeedback is aimed at the activities of the brain. It
uses electrodes placed on the scalp in order to read EEG signals. These
signals are then fed into a computer for analysis and the results are
given back to the subject, either visually or aurally. With some practice,
it is possible to guide the brain to produce specific EEG patterns. For
example, people can train themselves to achieve altered states of mind
by controlling their alpha waves. Alpha waves are frequencies between
8 and 12 Hz that are often associated with a state of meditation. Through
the use of a neurofeedback system, one can learn to recognise and eventually
gain some control of the burst of alpha waves and enter a state of heightened
awareness.
- Listening to music has often been regarded as a passive activity. Yet
neuroscience teaches us that every moment of consciousness also includes
reaction in addition to sensation. Consciousness is driven by massive
amounts of neural activity involving sensory and motor organs, and the
brain, whose main purpose is to turn sensation into behaviour. It is hard
to picture in this scenario why nature would have evolved the ability
to sit back and watch the world pass by, or simply enjoy listening to
music. I am a stronger believer, however, that watching the world pass
by and listening to music are not, in fact, a passive activities at all
- From a fundamentally neurological point of view, our natural response
to music is to move our body; hence our tendency to involuntarily nod
our head and tap our feet to the sound of music. We can, however, suppress
this neural predisposition at will, because the brain can choose to not
activate the behaviours that were supposed to be set in motion by incoming
sensations. But even then, it is likely that at its most fundamental levels,
the brain still processes music in terms of movement.
- The amount of information that flows in the brain is immense, but we
have evolved pretty good strategies to react to sensations as quickly
as possible. The bottom line is that we cannot afford the time that it
would take to wire from scratch billions of neurones for every leap of
consciousness. One of the strategies that the brain has evolved to deal
with huge amounts of information flow and reaction delays is to make predictions.
Scientists generally agree that the brain knows how it will react prior
to actually processing the whole range of incoming sensory information.
The brain formulates an image of what is expected, and weighs it against
the properties of the external world as reported by the sensory organs.
The matching between the internal and the external worlds generates behaviour.
The internal representation is then upgraded and the next prediction is
formed, and so on. Thus, a lapse of consciousness cannot exist without
a context; there is always something about what has just happened that
prompts the brain to predict what is likely or unlikely to happen next.
This is music. The brain is musical and music is our soul.