What is the secret of the fascinating power of music?
Music surrounds us everywhere. At the sound of a powerful orchestral crescendo, tears come to my eyes and goosebumps run down my back. The musical accompaniment enhances the artistic expressiveness of films and performances. Rock musicians make us jump on our feet and dance, while parents lull the kids with quiet lullabies.
The love of music has deep roots: people have been composing and listening to it since culture originated. More than 30 thousand years ago, our ancestors already played stone flutes and bone harps. It seems that this hobby has a congenital nature. Infants turn to the source of pleasant sounds (consonances) and turn away from unpleasant (dissonances). And when we are in awe of the final sounds of a symphony, the same pleasure centers are activated in the brain as during a tasty meal, having sex or taking drugs.
Brain processing of music is based on hierarchical and spatial principles. The primary auditory cortex, which receives inputs from the ear and (through the thalamus) of the lower auditory centers, participates in the initial processes of music perception, for example, analyzing the pitch (tone frequency). Under the influence of experience, the primary auditory cortex can be reconfigured – it increases the number of cells that have maximum reactivity to important sounds and musical tones for a person, which affects the further processing of musical information in the secondary auditory areas of the cortex and the auditory associative zones, where more complex musical characteristics (harmony, melody and rhythm).
When a musician plays an instrument, the activity of the motor cortex, cerebellum and other brain structures involved in the planning and implementation of specific movements, precisely aligned in time, increases.
Why is music so important to man and has such power over him? Neurobiologists have no final answers yet. However, in recent years, some data have begun to appear on where and how the processing of musical information takes place. The study of patients with traumatic brain injuries and the study of healthy people with modern methods of neuroimaging led scientists to an unexpected conclusion: there is no specialized music center in the human brain. Its processing involves numerous areas dispersed throughout the brain, including those that are usually involved in other forms of cognitive activity. The dimensions of the active zones vary depending on the individual experience and musical preparation of the person. Our ear has the smallest number of sensory cells compared to other senses: there are only 3.5 thousand hair cells in the inner ear, and 100 million photoreceptors in the eye. But our mental reactions to music are incredibly plastic, because even short-term learning can change the nature of the processing of the “musical inputs” by the brain.
Music in the head
Before modern neuroimaging techniques were developed, researchers studied the musical abilities of the brain, observing patients (including famous composers) with various disruptions in their activity due to injury or stroke. So, in 1933, the French composer Maurice Ravel developed symptoms of local brain degeneration – a disease accompanied by atrophy of certain sections of brain tissue. The composer’s mental abilities did not suffer: he remembered his old works and played scales well. But he could not compose music. Speaking about his alleged opera “Joan of Arc”, Ravel confessed: “The opera is in my head, I hear it, but I will never write it. It’s all over. I am no longer able to compose music.” He died four years after an unsuccessful neurosurgical operation. The history of his illness gave rise to the idea among scientists that the brain is devoid of a specialized music center.
The mortgage was confirmed by the case of another famous musician. After the stroke suffered in 1953, the Russian composer Vissarion Shebalin was paralyzed and stopped understanding speech, but until his death, which followed 10 years later, he retained the ability to compose. Thus, the assumption of independent processing of musical and speech information turned out to be true. However, later studies have made adjustments related to two common features of music and language: both mental functions are a means of communication and have a syntax – a set of rules that determine the proper combination of elements (notes and words, respectively). According to Aniruddh D. Patel from the Institute of Neuroscience in San Diego, studies conducted by neuroimaging methods indicate that the correct design of linguistic and musical syntaxes is provided by the frontal (frontal) cortex, and other parts of the brain are responsible for processing related components of language and music.
We also got a complete picture of how the brain reacts to music. The auditory system, like all other sensory systems of the body, has a hierarchical organization. It consists of a chain of centers that process the nerve signals traveling from the ear to the highest part of the auditory analyzer – the auditory cortex. The processing of sounds (for example, musical tones) begins in the inner ear (cochlea), which sorts out complex sounds (made, for example, by violin) into constituent elementary frequencies. Then, through the fibers of the auditory nerve, which are tuned to different frequencies, the cochlea sends information in the form of a sequence of neural discharges (pulses) to the brain. As a result, they reach the auditory cortex in the temporal lobes of the brain, where each cell responds to the sounds of a certain frequency. The frequency tuning curves of neighboring cells overlap, i.e. there are no gaps between them, and a frequency map of sounds is formed on the surface of the auditory cortex.