31 Oct The empathic role of mirror neurons (GIOVANNI FRAZZETO)
The word ‘empathy’ made its first appearance in the English language in 1909, as a translation of the German ‘Einfühlung’, in turn introduced by the German philosopher Robert Vischer, which means ‘feeling into’ Vischer first talked about Einfühlung referring to the field of psychology of aesthetic experience to remark how an observer perceives a work of art he or she contemplates. In front of a painting, a sculpture or another type of artwork, a viewer empathizes, or fuses, with it – just as I was absorbed into Caravaggio’s painting at the gallery in Rome.
Over time, the term empathy was used not only to explain our relationship to inanimate objects, but also to describe how we can instinctively understand other people’s mental states.
Empathy lets all kinds of emotions reverberate amongst us. It is the capacity to recognize and identify with what another person is thinking or feeling, and to react with a comparable emotional state.
Empathy is the backbone of our social life. Whether in thoughts or acts, it intrinsically demands an interaction with others. It has the power to spread joy, euphoria or laughter, but it also helps mitigate difficult circumstances – for instance, alleviating negative emotions. Anxiety, guilt, sadness, despair are somewhat eased if shared with others. Empathy is like an invisible bond with the power to unite us to other human beings and blur the dividing line between ourselves and them – as in the case of me and Hamlet during Ben’s performance.
In this chapter I am going to use theatre as a vehicle to understand empathy and how emotions are perceived and communicated.
A mirror for our emotions
The Spanish neuroscientist Santiago Ramon y Cajal (1852–1934) wrote: ‘Human brains, like desert palms, pollinate at a distance.’ It is fascinating that he should be the author of such an affirmation, because his work paved the way for the understanding of how neuronal connections are established. Thanks to a silver staining technique developed by the Italian scientist Camillo Golgi, Cajal demonstrated that the nervous system is not an uninterrupted bundle of neurons wound around itself, as was generally believed at that time, but rather was composed of neuronal cells as separate units coming into contact through their ramifications. And we definitely need those neuronal contacts in order to empathize.
A new and attractive framework for the understanding of empathy emerged with the discovery of ‘mirror neurons’, cells that have revolutionized how we regard our emotional connections with others. The discovery was as important and sensational as it was serendipitous. Back in the 1980s in a laboratory in the Italian city of Parma, Giacomo Rizzolatti, Vittorio Gallese and colleagues were investigating which brain areas were involved in the execution of movements. They noticed that a group of neurons in a region of macaque monkeys’ premotor cortex, called area F5, fired when the monkeys performed a simple action such as reaching for a bite or grabbing a peanut. But F5 neurons were activated only if the movement involved an interaction between the agent of the movement and an object, and not if the movement had no specific goal or intention. Simply moving the arm with no goal was not enough for the neurons to scream their involvement in the detection instruments.
To deepen their findings, in the mid 1990s, the researchers then implanted electrodes in the monkeys’ brains to record activity from individual motor neurons in area F5 while they gave the monkeys different objects to grasp. Here is where they faced a huge surprise. The moment they picked an object to hand on to the monkeys, the electrodes signalled some neuronal activity. To the researchers’ amazement, the recorded activity came from exactly the same neurons that would also fire when the monkeys picked the same object themselves. Basically, the neuronal activity of observing an action mirrored the activity of performing the same action.
These results were extremely thrilling because until then scientists had thought that the area F5 was involved exclusively in motor functions. Instead, the newly discovered mirror neurons displayed motor and perception capacities. When the monkey watched an action, even though it did not move a muscle to reproduce it, its mirror motor-perceptive system was activated as if the monkey were executing what it saw. In other words, the brain simulated action. After these exciting discoveries in monkeys, everybody asked: do humans also have mirror neurons?
Applying electrodes deep into the brain of a person in search of single neuronal activity is not a feasible procedure. What you can easily do in humans is to use less invasive techniques such as fMRI. fMRI does not detect the electrical activity of single neurons, but the blood flow in the whole brain, so fMRI data would reveal areas that are active during both the observation and the execution of actions and might, therefore, contain neurons with mirroring functions. That is why in humans you cautiously talk about ‘mirror-neuron systems’ rather than single mirror neurons.
One of the first studies of mirror neurons in humans asked participants to watch experimenters make finger movements and then imitate those same movements. The results identified two cortical areas with mirroring functions. One, located more towards the front of the brain, includes the inferior frontal gyrus (IFG) (Fig. 13) and the adjacent ventral premotor cortex (PMC). Another, located further back, is the inferior parietal lobule (IPL), which can be considered the equivalent of the monkeys’ area F5.
The IFG is located within Broca’s area, which is the brain’s main language area. This suggests that the mirror-neuron system may have been an evolutionary precursor of neural mechanisms for language. Speaking of evolution, it seems that the IFG may have evolved to be the common denominator underlying empathetic understanding across different emotions. A study testing which brain regions responded specifically to four basic emotions – happiness, anger, disgust and sadness – revealed that the degree of activation in the IFG correlated positively with the levels of empathy shown towards all of them.
So, mirror neurons basically give us a second, more intuitive pair of eyes that shortcut the comprehension of the actions we witness. They allow us to apprehend an action we observe by making us simulate it in the brain. We internally know what someone else is doing.
This idea soon made researchers believe that the role of mirror neurons within the context of perceiving and simulating a simple action was only a tiny part of a more evolved mirroring system we use to empathize and understand each other’s emotions. It only had to be uncovered! Emotions are contagious. How many times do we find ourselves cringing, smiling, or even laughing if someone else does it in our presence and before our eyes? Not only at the theatre, but in all kinds of daily social interactions.
Indeed, one of the first studies that investigated the empathic role of mirror neurons in humans adopted a paradigm of observation and imitation of facial emotional expressions. The study consisted in letting participants first observe and then imitate facial expressions of the six primary emotions – joy, sadness, anger, surprise, disgust and fear. The mirroring network responded during both actions, especially during imitation. In addition, the amygdala was also involved. This revealed the link between the human mirroring system and the limbic brain. Anatomically, this link is achieved via a region in the brain called the insula, which was also activated during the procedure.
Researchers are moving forward in exploring how we empathize with all kinds of emotions. One study imaged the brains of people who first themselves inhaled nasty odours and then watched a film of an actor wrinkling up his face in a disgusted look. Both when feeling disgusted and when watching someone being disgusted, their insula fired up. Even more interestingly, one study investigated ‘tactile’ empathy, that is, how we react to the sight of others being touched. Do we feel the touch ourselves? Indeed, the results indicated that the same area in the cortex would fire in people when they were lightly touched on their leg and when they watched video clips of others being touched in the same spot. Most recently, another study revealed that the mirror-neuron system was involved in individuals who watched others yawn.
Joy, Guilt, Anger, Love : What Neuroscience Can–and Can’t–tell Us About How We Feel