Music Theory

Beautiful music one the greatest achievement of humans.  The sense of musical beauty is elusive and does not require complexity or even great skill, although beautiful music is more likely to occur when the composer and performers are accomplished and devoted to their art.

Music describes a remarkable variety of human activities that involve making sounds. Musical sounds convey meaning without the decoding required for language sounds. Some musical phrases are copies or facsimiles of alarm cries, bird songs or human shouts and cries that attract attention, signal danger and express emotion. Bird songs are most easily identified with musical melodies and composers have copied a bird song as a theme for a musical composition.
Music comes in all shapes and sizes. Some music is spontaneous and easy to make. A folk singer may be quite charming, strumming simple chords on a guitar, singing a plain song in a spontaneous and undisciplined manner. Other music requires years of disciplined study and practice and involves complex concepts and notation systems.

Musical expression begins with and is usually associated with body movement. Music begins with rhythm, repeated vocal sounds and stylized body movements. Dance is an elaboration of gestures and body movements associated with both performing and enjoying music. Children will spontaneously dance and sing and raise their arms above their head and sway from side to side creating a momentary ecstasy that is repeated at all ages and many difference contexts from temples to discotheques.


Musical instruments are variations on tools used for other purposes and all you need to begin a music composition is your own voice and body movements. If you strike two sticks together, you are beginning to play music. Rhythm is essential to music and originates in nature before and aside from musical sounds. A musical phrase obtains meaning when it finds a compatible brain receptor and activates an emotional or behavior response. Humans respond emotionally to music and experience a range of emotions from elation to despair. I respond to beautiful music with tears. This a version of crying in response to the sadness or joy expressed by the music; the intense emotional response also feels like admiration and gratitude for the beauty of the composition and the skill of the performers.  I am most likely to cry when I hear a female singer who expresses herself in a strong, clear voice with sincerity and passion.

Musical information consists of pitch, loudness, timbre, location, and movement of the sound source. A combination of sounds of different pitches produces harmony and a sequence of pitches becomes melody. Timbre describes the harmonics in a sound that give it recognizable qualities. A range of timbres in human voices provides for the sound identification of individuals. You can identify who is talking from voice timbre and intonation, just as you can identify a trumpet, an oboe or a violin.

Formal music is assembled into language-equivalent structures, suggesting phonemes, syntax and semantics. Music performance involves many agreements about instrument design, pitch assignment, the meaning of notation so that groups of people can produce harmonious sounds with compatible rhythms. One musical agreement is about the pitch interpretation of notes. The standard concert pitch, A, for example denotes a sound with the principle frequency of 440 cycles per second. When an orchestral assembles, each instrument is tuned to the standard pitch. Other agreements determine the pitch meaning of other notes.

The piano is the reference instrument; its keyboard represents a standard for the pitch meaning of each note. Scales are standard sequences of intervals that are used in orchestral and popular music.  The Greek philosopher, Pythagoras, determined that if you divided a vibrating string in half, you would hear an octave at double the fundamental vibration frequency. The octave interval sounds like the same note is being played, but at a higher pitch. Since we hear intervals differently as the pitch increases, a well-tempered tuning has been adopted that adjusts the wave frequency difference of intervals, which decrease as the pitch increases.

While classical music written in Europe is appreciated as high art and performed by skilled musicians, musical styles and forms in the 20th century proliferated and incorporated sounds from all over the planet. At the same time electronics advanced so that recorded music became the most popular way to experience music. The science and technology of sound physics and the neuroscience of sound perception advanced remarkably.

I have enjoyed many different expressions of this technology and continue to learn about sound synthesis, instrument modelling, recording and editing sound. All these activities inform about the way our brain processes sound. The main distinction in the world of sound is between music which is intelligent and pleasing and noise which is neither.

Humans have a strong tendency to bond to sounds early in life and prefer to hear or sing simple songs they learned earlier. Popular songs can be repeated throughout their life with the same strong feelings of identity and comfort. Simple melodies have the greatest appeal and widest audience, because they are easy to remember and resemble the simple phrases of ancient animal communication. Songs, of course, combine words and music and are potent in eliciting emotional responses. The combination of words and sounds reveals the relationship between music and spoken language. Without music, religious meetings would be boring and movies would be disappointing.

A singer communicates emotionally with the audience, using gesture to emphasize the emotional values of a song. I must admit that singers who indulge in exaggerated and strenuous gesturing and frantic dance often offend me. In contrast, I am enchanted to hear and watch Andrea Bocelli, the blind and eloquent Italian tenor. Because he is blind, he stands motionless on the stage with his eyes closed. Bocelli sings with a perfect composure that is consistent with the mastery of his art. He is a Buddha.

Chanting is soothing to humans and group chanting can induce euphoria that some humans call a “religious” or “mystical” or “spiritual” feeling. The benefits of chanting are independent of the meaning of the words, although meaning can enhance the experience of chanting. Words used in chants are simple and often have a musical quality of their own.

Repeating the same phrase rhythmically has a trance-inducing power. If you combine chanting with dancing or just holding you arms in the air, swaying back and forth, you become euphoric and feel bonded with others in your group.  Music induced trances work at Woodstock, folk concerts, rock concerts, support groups, churches, all night voodoo dances and on camping trips, sitting around a camp fire. The latest version of chanting is rap, a monotonous monologue accompanied by rhythm that combines  simple narratives and repeating phrases.

Musical sounds are processed in the temporal lobes in humans, especially in the left planum temporale. Pitch recognition is a built-in talent that is not uniformly inherited. Some humans are described as “tone deaf” when they cannot identify or reproduce pitches they hear. Pitch like, color is a subjective experience that correlates more or less with the wave frequency of the source. Sounds have a fundamental frequency with timbral harmonics as multiples of the fundamental.  The same pitched note played on a trumpet and piano can be readily identified even though the waveforms on an oscilloscope are quite different.

Bendor and Wang discovered neurons near the anterolateral border of the primary auditory cortex in marmoset monkeys that respond to both pure tones, providing a neural correlate for pitch constancy. They stated: “Pitch perception is critical for identifying auditory objects, in music and speech. Pitch is the subjective attribute of a sound's fundamental frequency (f0) determined by the temporal regularity and average repetition rate of its  waveform. Spectrally dissimilar sounds can have the same pitch if they share a common f0.
Platel et al used PET scanning to study the cerebral activation of volunteers performing 4 tasks: selective attention to pitch, timbre and rhythm and semantic familiarity with tunes. They observed that the left hemisphere was more active for familiarity, pitch and rhythm determination. The right hemisphere was more active for the timbre task. The familiarity task activated the left inferior frontal gyrus and superior temporal gyrus. The pitch task activations were observed in the left cuneus/precuneus. The rhythm task activated left inferior Broca's area with extension into the neighboring insula, suggesting the processing of sequential sounds similar to word recognition processing.

From the Sound of Music by Stephen Gislason

Revised Jan 2015

Music is Movement

Movement is the most fundamental feature of humans and other animals. The brain is the organ of the mind and the organ of movement. The brain is a matrix of meaningful connections between the body inside and the environment outside. Our speech and music grow from spacetime motion and communication with sounds. There is rhythm in our motion, in the sounds we hear and the sounds we make. Our languages emerge from spacetime maps and rhythmic sounds. We speak in terms of movement through spacetime, and of journeys both literal and metaphoric. We project out minds into the world and merge with the world of continuous changes and constant motion.

Humans act on the world through praxis or skilled movements. The root adaptive task is to learn what movements are required for survival today. Ten thousand years age, if you were male, you learned to throw a spear, catch a fish or carry a deer carcass on your back. Today, you learn to learn to throw a football, move a pen across a paper surface, push keys on a keyboard and control movement with a mouse or joystick. Musicians play instruments that require skilled movements and add a variety of dance-like body movements or really dance as they play. Virtuoso musicians acquire fast motors skills and accurate motor memory to play complex passages accurately.

Humans learn by imitating what they see and hear. An astute observer knows that learning movements is a mimetic task and recognizes that observing and performing movements is closely integrated. Sensory and motor systems are not separate entities. One well studied mechanism that underlies mimetic learning has been called mirroring. Mirror neurons were originally discovered in the ventral premotor cortex of the macaque monkey.  These neurons are active when a monkey performs a motor act and again when the monkey, at rest, observes another individual performing a similar motor act. The term mirroring is somewhat in error since similarity is based on a common purpose or goal of the action such as grasping more than a mirror image of the movements performed. 

Learning movement skills is so implicit in life experiences that most of the lessons are not recognized as such and most of the practice is built into the daily experiences of life. To learn, you copy the skillful movements of others and practice these movements until you match or surpass the teacher's skills. Humans create neuronal models of their own behavior and the behavior of others, remember and communicate these models. We can simulate experience and anticipate what we are going to do in the future. We can practice skills in advance so that can improve our performance. We expand this modeling capacity by using musical instruments. We can learn to handle sounds much like objects and do sound and symbolic transactions with each other. Movement originates in several areas of the brain. The final signals to muscles to contract emerge from the thalamus and motor cortex and travel along the spinal cord to the motor neurons in the anterior horn of the spinal cord grey matter. The spinal motor neuron sends a signal along a peripheral nerve to the muscle cells. The cerebellum does the fine-tuning of coordinated movements by adding to the signals emerging from the motor cortex. The parietal cortex stores maps that connect body movements with spacetime and recall learned patterns of movement. If the motor cortex is damaged, you are paralyzed. If the cerebellum is damaged, movement coordination is peculiar or lost. If the parietal cortex is damaged, you retain movements but learned motor skills may be missing and you may ignore part of your body as if it did not exist. A typical parietal deficit is that you cannot perform learned movements such as dancing or playing and instrument.

Three cortical regions control voluntary movement:
Primary motor cortex M1
Premotor cortex (PM)
Supplementary motor area (SMA)

The simplest idea of the brain begins with a sensory input entering a processor that then decides what to move and sends motor outputs to the motors which are muscle cells. The first complication in this model is that the motor cortex has sensory input and the sensory cortex has motor output.  The second complication is that some movement is generated in response to real-time sensory input and other movement is generated from memory that operates like internal sensory input.

The body is mapped onto the sensory and motor cortex. Smaller body parts such as the fingers, lips and tongue that are used for fine manipulative movement occupy larger areas of the motor cortex than larger body parts such as arms and legs that are involved in more vigorous movements such as throwing and walking. A smaller cortical area (SMA) in front of the motor cortex contains a separate body map and at least 4 other regions of the brain contain body maps. While cortical maps exist, the regions in the map are not discrete. If the map is displayed as pieces of a jig saw puzzle, the pieces are not placed side by side, but overlap. The arrangement would be easier to understand if motor neurons were assigned to one body part and made point-to-point connections that were stable over time.  However, the real cortex appears to have a dynamic map and a scheme of connections based on fields of activity that converge and diverge in complex patterns. Over time, the pieces of the map change with learning and practice, so that the construction of cortical connections is in flux. Schieber described general and specific activation.  "During natural movements of discrete body parts, activity is distributed across a wide territory in M1. In monkeys trained to perform individuated movements of each finger, single M1 neurons are active during movements of multiple fingers and neurons throughout M1 hand area are active during movement of any given finger. In humans, performing movements of different fingers, activity is distributed over the primary sensorimotor hand area whether the subject is moving the whole hand or a single finger."

Neuroscientists now make distinctions among many components of movement. For example, the preparation to make a movement is regarded separately from the volley of signals sent to implement the movement. Scheiber stated:  "Neurons in M1, SMA and PM discharge at the highest rate while a subjects waits to move in particular direction… during the delay between instruction and movement triggering, PM and SMA appear to store information on the direction of the impending movement… this represents (the retrieval of) stored information...To pick up a pencil, for example, you may glance at the pencil and then move your hand to the same place.

Insight into how cue direction is transformed into movement direction has come from tasks in which these two features were experimentally dissociated, similar to glancing at your pencil in a mirror and then reaching to pick up the real pencil instead of a mirror image…The cue direction is transformed into movement direction in the area principalis (of the frontal lobe) during the delay period… information is sent to M1 at the time of execution."

Revised Jan 2015

The Musical Brain and other topics presented at Persona Digital Studio are from the book, The Sound of Music by Stephen Gislason

For additional reading see Neuroscience Notes and The Human Brain, available from Persona Books