Neurobiology of musical experience
By: Mara Dierssen (Biomedia)
Music is a complex phenomenon, difficult to define from a neurobiological perspective.
From the perceptual point of view, combined variations of practically all the acoustic parameters are produced in it, giving the simultaneous and the successive time, chords within sets of chords and sets of timbres inserted in changing and dynamic harmonic frames.
From the executive point of view, music requires the development and integration of complex motor programs and high levels of competence in visual-spatial, sequential and proprioceptive tasks in relation to specific motor tasks.
Finally, there is a musical quality that is especially relevant for certain sectors of professional musicians, such as conductors or composers.
It is about tonal memory, or memory for sequential configurations of tones, and auditory imagery or hearing, understood as the musical auditory representation in the absence of physical sound.
Darwin expressed his total misunderstanding about the biological function of music in the human being.
However, it is certainly a cross-cultural phenomenon, like the existence of language or emotions, and whose magnitude inexorably leads to the conclusion that there is a basic impulse in our brain that encourages us to listen or produce music and, therefore, there must be a neurobiological substrate that supports such a function and that justifies the implicit musical ability of the human brain.
Indeed, to be something devoid of concrete significance, the effort expended in creating or reproducing music is really enormous.
Not to mention the economic investment involved and the countless works that exist, transcribed or not.
Musical ability, however, and unlike linguistics, is not universal, but is developed only by some people.
The genetic or environmental causes that determine the existence or development of such ability remain unclear, but it is clear that musical performance and composition involve a considerable number of perceptual-visual, sensory-auditory, and sensorimotor skills.
A walk through the mind: the morphological substrate
In order to approach the musical experience from a scientific perspective, with the network of processes that intervene, both in the cognitive and emotional spheres, we have to start a brief journey through the labyrinths of our brain.
It is not an easy task, since it is the most complex structure of all we know, whose construction does not follow known principles or purposes.
The brain contains about one hundred billion neurons (the same order of magnitude as the stars in the Milky Way), which Don Santiago Ramón y Cajal defined as’ the mysterious butterflies of the soul, whose beating wings who knows if one day will clarify the secret of mental life ‘.
The neuron, in effect, is the functional unit of our brain, although it is not alone in the mission of building the informational signals of our brain.
Other cell lines also participate in the generation and modulation of brain activity, allowing, for example, information to travel at enormous speed along nerve pathways.
The neuron is characterized by having a complex cellular machinery, basically at the service of communication with other neurons.
This machinery is orchestrated from the nucleus through the activation (or expression) and the silencing of specific genes with a temporal rhythm and subject to the events that occur in the cellular micro environment.
To establish communication with other neurons, each one of them launches extensions (axons) that, like long cables, reach the body or the extensions of other neurons, the point of contact being called synapses.
But what is the language that neurons use? It is an electrical and chemical language, so that if we introduce a thin electrode inside the neuronal body we can detect the presence of electrical activity in it.
When this electrical current, the nerve impulse, which propagates through the neuronal processes, reaches the synapses, tiny amounts of chemical molecules are released into the environment, which we call, based on their neurotransmitter function.
These molecules transmit information that is interpreted by the target neuron, and thus, when it receives the chemical molecule, a whole series of cellular changes take place inside it, affecting even the genetic machinery.
Neurons are in turn organized into neural networks that share similar information processing mechanisms, so that specific elements of specific processing can, in fact, locate.