The Cells of Social Consciousness
What makes us human? Humans possess the capacity for language, empathy, internal dialogue and emotions. However, before we were capable of such characteristics, we first needed to develop consciousness. It is consciousness that establishes our understanding of self and other. Here then, with the emergence of consciousness is the birth of subjectivity within a complex social network. So what then allows us to possess a consciousness? While the neural basis of consciousness remains a mystery, resent research has uncovered two classes of cells that could play major roles in organizing our capacity for social interactions. It seems that spindle neurons and mirror neurons could be responsible for separating us from the rest of the animal kingdom.
Spindle neurons, also known as VENs, were first discovered in the late 1990's by Esther Nimchinsky working with Patrick Hof and are found in the anterior cingulated cortex, ACC, of various primates. Working with John Allman, an expert on the evolution and anatomy of primate brains, they examined brain tissues of over 50 species. The team found that spindle cells appear in higher primates in greater numbers as species ascend the evolutionary "tree," with a few found in orangutans and tens of thousands in humans. Further research by Allman reveals a second, specific site containing these cells, the frontoinsular, FI, cortex, again only in humans and advanced primates. As Christof Koch, a neuroscientist working at Caltech, explains, these appear to be the only cells unique to humanoids (2). One must now ask, what role do these cells play and why are they only present in the most developed primates?
The ACC is associated with emotions and regulation of autonomic activity (4). The ACC essentially acts as a control hum mediating thought, feeling and the body's response to these feelings (2). The FI also appears to be associated with emotion, in particular, the responses one has to others. Studies by Andreas Bartels and Semir Zeki of University College London show activity in the FI and ACC in response to viewing an image of a loved one. Other studies conform to a pattern of activation in these regions in response to value judgments within a social context (2). The cells themselves possess large axons and dendrites, optimal for rapid transmission of action potentials, and receptors for serotonin, dopamine and vasopressin, which are associated with bonding, emotion and love. This has lead Allman to believe that these neurons are designed for rapid regulation of behavior in within a complex social environment (2), (5). For instance, it is favorable to instinctively know how to react to a loved one in need, there is no need to critically ruminate over her character. While Allman's theories are still speculative, there is certainly merit for further examination of the role of spindle neurons.
Spindle neurons, however, have received little publicity. Instead, there is a buzz in the scientific community over the discovery of mirror neurons. Giacomo Rizzolatti et all and Gallese et al. working at the University of Parma, Italy, first published their discover of "mirror neurons" in 1996. The discovery began with an observation of cell activity in macaque monkey brains. A region of the monkey brain, the ventral premotor cortex, referred to as F5, has been known to contain cells that become active before a monkey acts. This zone is associated with preparing for and planning movements. For example, these cells would have a particular firing pattern visible before a monkey eats a peanut. The research by Rizzolatti and Gallese show that these cells will also fire with the same pattern when the monkey sees another monkey eat a peanut (6). These cells have since become known as mirror neurons.
In addition to firing in response to viewing a monkey eat a peanut, mirror neurons also become active when the interaction between the observed monkey's hand and the peanut is obscured from the observing monkey's view. This indicates that mirror cells are assessing the situation and are filling in an expected consequence of the action (7). Another class of mirror neurons, "audio-visual mirror neurons," become active in the same area, but in response to any sounds associated with the action. These neurons seem to play an important role in survival as they allow for the quick processing of the intended actions of others in response to visual and aural cues.
It has since been discovered that humans, too, possess mirror neurons, but as part of even more developed and complex systems (3). As with monkeys, the mirror neurons in humans fire equally in response to action execution and action observation. These cells become activated in the premotor and parietal cortices, and are somatotopically organized. That is, there are various distinct regions of these cortices that activate in response to actions associated with a hand versus a mouth (7). For instance, "communicative mirror neurons" fire during speech and when viewing the motions of a mouth associated with speech, but mirror neurons that activate in response to a hand being raised will not respond to the speech. In both monkeys and humans, mirror neurons appear to be associated with specific actions and stimuli, but why have we evolved these highly specialized cells?
Gallese has proposed that the mirror neuron mechanism is at the base of action understanding (7). This involves first, a mental process of simulation. As the same neurons fire in response to viewing a hand slap a table as fire when actually slapping a table, these mirror neurons allow an observer to recreate an action within her mind. However, this process of simulation is not an active or conscious, it is an automatic response to the perception of any situation in which an agent is defined (7). Whether the agent is the observed or the observer, there must be someone who performs an action in order for these cells to activate. Mirror neurons, then, allow the perceiver insight into the intent of another agent, a crucial aspect of existing in a social atmosphere, if not a necessary part of social interaction (6). As, Gallese explains from other experimental data, successful perception and successful action both require the capacity to anticipate: to anticipate sensory information and to anticipate the product of action. Action understanding is this unconscious simulation, or modeling of agent, object and action, designed to assess the likely consequences of the interplay between the three (7).
Social cognition has become, in part, a function of insight into the other through mental simulation, thus giving a form of experiential insight, allowing the self to relate to the other on an empathetic level; we do not view the other through mere abstract reasoning, we rather feel what they feel (3), (7). Further research has been done to examine the relationship between VENs, mirror neurons and autism, while the details of these experiments will not be discussed here, the belief is that limitation of VENs and mirror neurons can inhibit the development of children into fully functional social beings, as VENs assist with rapid social intuitions and mirror neurons permit the social experience of empathy and key aspects of social referencing (1), (8).
If we are to accept that these two classes of neurons could be responsible for the development of social consciousness, a whole new world of questions open up. Do varying frequencies of these neurons affect what kind of person we become? What implications do these findings have for the writings of the great thinkers such as Hegel and Heidegger? How do these neurons shape social constructs built on subject/objectivity? Are these neurons responsible for ethics? The philosopher Emmanuel Levinas writes on a type of ethics based on the inter-human, in which he describes one having a duty to the other resulting from the-face-to-face encounter with the other: in encountering the other, one finds that they are constituted by not only himself, but also by the other. It seems that mirror neurons could be an unrecognized aspect of Levinas' philosophy. In finding these neurons, have we begun to tap into a mechanism behind a collective unconscious? If these neurons are even partially responsible for social consciousness, we open ourselves up to a whole new position on social thought.
1) Intuition and Autism: a Possible Role for Von Economo Neurons, Information on spindle neurons and their possible role in autism.
2) The Cell That Makes Us Human, An article from NewScientist on spindle neurons.
3) Cells That Read Minds, Information on mirror neurons.
4) Anterior Cingulate Cortex Regulation of Sympathetic Activity, Information of the roll of the ACC.
5) Spindle Neurons: the Next New Thing?
6) How Mirror Neurons Help Us Empathize
7) Intentional Attunement. The Mirror Neuron System and Its Role in Interpersonal Relations.
8) Autism's Smoking Gun?, Information on mirror cells and their possible roll in autism.