Mirror neurons – the missing link for consciousness? Eleanor Barrie, general category Consciousness. It’s a word that most people feel they understand, but scratch the surface and things become pretty complicated. For example, you yourself are acutely aware that you are conscious. You’re conscious of these words, and perhaps even a feeling of interest in where this article is leading. How are these mental experiences produced? For years researchers ignored consciousness as being too subjective for scientific study, but more recently it has become one of the most fascinating and complex problems tackled by scientists. How does a brain physically produce a conscious experience, and why did this ability evolve? We may have to turn away from our fellow humans and towards the even more mysterious minds of animals to find the answers to these questions. While some would say that consciousness is a unique property of human brains, others would argue that some animals possess this fascinating trait too. The fact remains that, to study consciousness, scientists often rely on experiments conducted on animals. There’s a good reason for this. Many animal behaviourists have suggested that consciousness may have evolved as a way to deal with living in social groups. Consciousness may have enabled social animals to understand the feelings and intentions of other individuals in the group. Being able to interpret the behaviour of others is certainly important in human societies, but it’s not just humans that are social animals. Bees, chimpanzees, and many others also live in social groups, so it seems logical to use these kinds of animals to study the evolution of consciousness. Recent research has suggested how humans and other animals might first have become “natural psychologists”, capable of reading each other’s moods and feelings. In 1996, neuroscientist Giacomo Rizzolatti and his colleagues at the University of Parma discovered a new type of nerve cell or neuron. These “mirror neurons” fire not only when their owners perform certain tasks, but also when they watch someone else perform the same task. Mirror neurons were first discovered in macaques, in a region of the monkey brain known as F5, which is part of the premotor cortex. The premotor cortex is used in planning and making movements, but in these monkeys it also seemed to be registering the actions of other individuals. It seemed as if the monkeys had taken the first step to understanding the minds of others. So how does this finding relate to humans? Studies have shown that Broca’s area, a region of the human brain involved in understanding language, is active when humans watch images of someone drumming their fingers, and also when the watcher tried to imitate the movement. Interestingly, Broca’s area is thought to be analogous to the F5 region in monkeys. It seems that mirror neurons may be an important step towards developing a “theory of mind”. If an individual possesses a theory of mind, they are able to read the intentions and beliefs of others – essentially they are able to put themselves in another’s place. Being able to understand others is one thing, but being able to imitate them is in some ways even more useful. It paves the way for learning by imitation, which is how humans have become the dominant species on this planet, passing on crucial information by cultural transmission. Mirror neurons may even have been instrumental in the evolution of language. Imitation is crucial in learning language, and the link between mirror neurons and the language area of the human brain suggests that these special neurons may be an important part of the process of language evolution. It seems both ironic and also appropriate that modern discoveries in the study of consciousness come from the brains of animals that were once thought of as mere automata, without conscious thoughts or feelings. The discovery of mirror neurons and its implications received relatively little press coverage outside of specialist scientific journals, but in fact it may be one of the most important advances in neuroscience in recent years. Mirror neurons have given us a tantalising glimpse of how consciousness may have appeared, and, through further research, they may even provide an answer to the great question of how the human mind evolved. Biography Eleanor Barrie recently finished a biology degree at the University of Oxford. She loves learning about science and communicating it to others, and is currently teaching science in a secondary school in London. She recently had her first article published in the Daily Telegraph while doing a work experience placement at the paper, and her ambition for the future is to be a science writer.