Updated: May 21, 2020
Neuroesthetic techniques for the treatment of Parkinson's disease
Introduction Vezio Ruggeri, professor of Psychology for the Performing Arts at the La Sapienza University of Rome, in his manual "Aesthetic experience: psychophysiological foundations for aesthetic education" suggests:
‹‹ The body, with its muscles, is like a musical instrument, for example a large harp. Anyone who has never seen the musical instrument […] would have difficulty imagining that such a wealth of sounds could arise from the movement of strings of different length and of different thickness: from strings differently stretched! The body has more muscles than the harp has strings! The muscles of the body play for its author. The music corresponds to the subjective experiences generated by the game of tension of the muscles. ››
Human emotions have a deep physiological basis, indeed they could be considered as the result of different muscle contractions, of different melodies played by our "harp". If we combine this image with the idea of resonance we understand how in theatre the actor, skillfully orchestrating both mind and body, can reverberate his notes also in the spectator's "harp": the actor can conduct dynamics of waiting, suspensions , surprises and resolutions that resonate directly in the space of action shared with the viewer.
The intertwining between tension and pleasure is full of nuances: it is therefore possible to hypothesize how, organically, there is a pleasure of the spectator induced by the resonance of the respective mirror systems at a psychomotor, preconceptional, preinterpretative and, in a broader sense, rhythmic level.
The dialogue between theatre and neuroscience has therefore been deepened in order to understand the brain mechanisms underlying theatrical production and, consequently, demonstrate the healing properties that the performing arts can offer in the psychophysical rehabilitation of neurodegenerative diseases that afflict the intentional motor sphere, such as Parkinson's disease.
In this paper, therefore, the study on the mirror properties of the human being was analyzed in detail, from the discovery to its medical-psycho-philosophical implications, and we focused on three fundamental aspects both for research on brain mapping and for the aesthetic experience - intention, imitation and empathy - examining them equally with a medical and humanistic approach. Finally, a survey has been included on the practical applications of theatre as complementary therapy in the rehabilitation of parkinsonian patients, ascertaining the limits of traditional treatments and introducing innovative and recent research realities, including PARKIN-ZONE onlus in Rome and PoppingForParkinson in London, which aim to create an interdisciplinary bridge for the recovery of the everyday life of those suffering from this disease.
MIRROR NEURONS: FROM A SERENDIPITY CASE TO THE BRAIN MAPPING
"Man is a social animal."
Thus Aristotle described us in his Politics. Yet humans are not the only animated beings to live in social groups or complex communities: just think, for example, of the colonial structure of ants. However, men have created the most articulated societies, governed by cognitive abilities that allow to project a representation of the self into the world and understand the intentions and emotions of the other. In other words, a social intelligence has evolved in our species. As suggested by the quote above, the study of the interpretation of the behavior of others is not at all recent: with the advent of brain imaging techniques, however, it has been possible to locate the brain regions involved in this processing.
1.1 The discovery Mirror neurons  were discovered entirely by chance in the first half of the 1990s in a laboratory of the Department of Psychology of the University of Parma by a group of researchers led by Giacomo Rizzolatti and composed of Vittorio Gallese, Giuseppe di Pellegrino, Luciano Fadiga and Leo Fogassi that, recording the neuronal activity of the F5 area of the anterior ventral premotor cortex of the macaques, verified the existence of a mechanism that allows the direct pre-linguistic and pre-reflexive understanding of the intentional transitive actions: the neurons of the F5 area, in fact, are highly specialized in coding motor behaviors oriented towards a specific purpose and discharge electricity as a response to only visual stimulations. There is an aura of mystery around the discovery of mirror neurons, as not even the members of the Parma team remember exactly what happened: Marco Iacoboni says that during a break Gallese would have unwrapped an ice cream, while another version involves Fogassi and a peanut. What is certain is that, at the same time, the electrodes implanted in a macaque recorded the discharge of a cell of the F5 area linked to the act of grasping: the motor neurons had activated not during the execution, but during the observation of the action performed by the researcher. Following subsequent experiments , the identical neurons were also found in the lower parietal lobe: therefore, when we look at a movement, these brain areas prepare to perform it. The words mirror neurons, in fact, indicate precisely that their activation implies a sort of rereading of the actions of others in the brain. One explanation for these discharges was that they could represent the concept of action : if these neurons actively participate in understanding the action, it follows that their discharge is the same both in observing the execution of a motion and in intuiting its meaning in the absence of his physical vision. Some experiments  showed that the macaque mirror neurons did not activate at the mere sight of an action, but only if the action was actually carried out: if the movement was mimicked, the cells did not discharge. Yet, the same experiments recorded that the mirror system of the macaques identified an action while only hearing its sound and that, in the absence of the vision of the final part of the action, the neuron was able to integrate the missing section by recognizing the sense in the partial sequence overall action, thus reinforcing the hypothesis that the mirror discharge represents the meaning of the act.
1.2 The mirror system in the human being Given the incredible genetic similarity between macaques and the human being, the question of whether or not the mirror system exists in man has clearly arisen to scientists: unfortunately, to date, no mirror cell has been registered in us. However, there is numerous indirect evidence of the presence of this mechanism: thanks to sophisticated brain imaging techniques, such as positron emission tomography (PET) and functional magnetic resonance imaging (fMRI), both non-invasive modalities, as in the subject of the experiment scanners are inserted only for a time varying between fifteen minutes and two hours, it was possible to identify mirror properties in the posterior parietal cortex and in the premotor cortex.
1.2.1 The revolution of neuroimaging It is necessary to keep in mind that with neuroimaging modalities  neuronal activity is not directly calculated, but the electrical signal generated by changes in the cerebral blood flow or by oxygen in relation to glucose is measured: for example, with PET it is determined glucose metabolism by means of the introduction of a radioactive element to activate the signal, while with functional magnetic resonance imaging the BOLD (Blood-Oxygenation Level Dependent) is calculated, i.e. a signal dependent on blood oxygenation that is generated through changes electromagnetic state of oxygenated hemoglobin with the activation of a certain area of the brain. Neuroimaging techniques have the advantage of simultaneously codifying the functioning of distant brain areas and of examining the deeper regions of the brain, which are interesting in psychiatry as they are the seats of the limbic system, which is the regulator of emotions. Furthermore, since the surveys are obtained in an almost harmless way for the subjects subjected to the experiments, it is possible to carry out a long-term sequence of tests which consist of even daily sessions. ‹‹ The result is similar to a sort of brain activity film ››  : even if the subjects are completely immobile, their motor system performs or simulates the actions observed.
1.2.2 Linguistic mediation As mentioned just above, these mechanisms have localized in the posterior parietal cortex and in that premotor mirror-like property: but the Broca area, which is linked in man to the processing of language, is often activated too. Therefore, the hypothesis has been put forward that the discharges of the parietal and premotor areas are simply a reaction to the linguistic representation of the action reorganized in the Broca area and that they have no connection with the mirror system of the other primates: by means of of the observation of an action performed with any part of the body, neuronal activity should initially be localized always in the Broca area. A research group led by prof. Buccino has demonstrated its groundlessness  : in fact, after showing healthy subjects videos of both transitive actions on objects and actions not aimed at objects, comparing them with static images, they found that the premotor cortex is always activated, as much for transitive actions directed to an object than the posterior parietal cortex only in the case of motions directed to objects, while the Broca area is never activated in the event that these acts are performed by parts of the body other than the hands and from the mouth. Therefore, since Broca's area does not discharge by means of movements performed with different effectors, but on the contrary, depending on the case, different parts of the brain are activated, the theory of linguistic mediation has no empirical value.
1.2.3 Between ballet and capoeira Human beings, however, possess a motor repertoire that goes beyond simple object-oriented actions and have unlimited ability in acquiring new possible motor skills: they have in themselves registered not only the anatomical skills of a movement, but also those recorded through learning. In fact, a particular action may appear in the motor memory of an individual who has long had experience with it, but not in the memory of someone who has never learned it. A research  conducted by dr. Calvo-Merini and colleagues studied groups of people with different motor skills acquired to investigate whether, in the observation of a given activity, the premotor and parietal cortices of individuals experienced in these skills were activated in the same way that in those of elements extraneous to the activities. Specifically, the experiment consisted of showing classical dancers and capoeira dancers videos on a black chromatic background, in order the discipline in which they were competent before and then what they did not know and simultaneously recording their neuronal discharges with the fMRI: in this way, both groups of dancers was stimulated by identical visual representations, with different experience, and consequent motor memory, as the only variant. In fact, ten professional dancers from the Royal Ballet of London, nine autonomous capoeira dancers and ten non-expert dance volunteers were involved; all subjects were right-handed and aged between 18 and 28, with normal vision and without any neurological or psychiatric background: in fact, although different dance styles involve a distinctive and consolidated muscle set, same-sex dancers generally have kinematically comparable movements. It must be underlined, however, how dance brings free will into play, or the intransitive movement of the whole body, the real object of this study. The results of functional magnetic resonance imaging recorded that when the dancers observed the discipline of which they knew the steps, their mirror system resonated louder, while, at the sight of the other dance, only 15% of their premotor and parietal cortex discharged. It has therefore been proven that there is a correlation between the motor baggage acquired during a training and the degree of activation of the mirror system and that motor learning probably modifies the mirror circuits.
1.3 The embodied simulation So what is the original function, in an evolutionary sense, of mirror neurons? One hypothesis is that they serve in the formation of a motor pattern that the observing subject can then quickly reproduce or to be able to learn by imitation. Certainly imitative behavior would not be possible without the presence of the mirror system, but mirror neurons are evolutionarily charged, even before imitating, to recognize and understand the meaning of the motor events of the other self: mirror neurons associate the visual information with the observer's motor knowledge, the observed movements take on meaning because they are part of a "vocabulary of acts" of the observing subject and can be understood only by virtue of that kinetic knowledge that allows performing an action and to recognize it if observed by means of the same neural pattern. However, the level of understanding promoted by mirror neurons is even more profound, as it also incorporates the intentions and mental states of others by means of the mental simulation of the action without resorting to explicit reasoning. This functional mechanism is called "embodied simulation".
1.3.1 The Theory of Mind In psychology, the innate ability to attribute a mental state to the other is called Theory of Mind  , of which there are two different variants, a radical one called Theory of Theory and a more moderate one known as Simulation Theory: according to the first, to assign mental states to others we act scientifically, that is, based on the observation of a behavior, we build a theory on these mental states and empirically search for evidence of them and therefore the mental states of others are the product of our reasoning; on the contrary, on the basis of the second theory, the other's point of view is adopted and the actions or states of others are automatically and unconsciously simulated. The discovery of mirror neurons supports the Simulation Theory at the expense of the Theory of Theory, as the observer undergoes brain motor activation in the areas of competence of the same muscle groups as the observed agent. The simulation evolves from the theoretical to the empirical level and becomes embodied: during the observation of an action, a chain of mirror neurons, called logically related, is activated, corresponding to all the movements necessary to implement the entire action so that they can simulate it in our brain even before it is completed together with the agent's intention. It is called embodied simulation not only because it is carried out at the neural level, but also because it uses the form of self-representation and it is from this mechanism that neurologically depends our extraordinary ability to enter into relationship with the other, empathy. Indeed, the mirror system could even be implicated in our aesthetic experience.
"To understand himself, man needs to be understood by the other. To be understood by the other, man needs to understand the other." Jorge Luis Borges
To be continued...
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