What is consciousness? It’s a pretty big question. For centuries, neuroscientists and philosophers alike have been having a stab at it. Freud had his ideas about the ‘id’, ‘ego’ and ‘superego’ which keep each other in check. MacLean reasoned that the brain stem drove all cognitive processes. Susan Greenfield has a unique view. She rejects the notion that the mind is something ‘airy fairy’ and incomprehensible. Rather, the mind and the brain are, in fact, simply one and the same.

  Describing the brain is very difficult. This is mainly because there is nothing like the brain in our known world. Nevertheless, many metaphors and analogies for the brain have been thrown around. Baars compared the brain to a theatre, self-compiled of memories. Susan Greenfield acknowledges this as the ‘Readout Fallacy’. Consciousness is where it stops. There is no voice to read out our thoughts. And if the brain is a theatre, then what is the audience?! David Chalmers believed that the material of the brain is irrelevant to the mind, and that consciousness is simply a property of the universe, like space and time. Greenfield challenges this with the “Thing Fallacy”. For if consciousness were a force, then how do you explain the effects of drugs such as Prozac and anaesthetics on consciousness? We can also use brain imaging to map conscious activity in the brain. Could consciousness therefore depend, if not on a certain area of the brain, on the presence of several components within the brain? Greenfield rejects this, because arousal can be generated in the unconscious brain. There is no qualitative factor in the brain which is sufficient to be necessary for consciousness. But could the mind actually be the physical brain? Could it simply be, as Steven Pinker asserts, “what the brain does”?

"There is no qualitative factor in the brain which is sufficient to be necessary for consciousness...
But could the mind actually be the physical brain?"
Greenfield hypothesises three key points. Firstly, emotion is the most basic form of consciousness. Secondly, minds develop as brains do, as neuronal connections grow from personal-experience based learning. Thirdly, the more you have of either the mind or the emotional state at one moment, the less you have of the other.

  In this book, Greenfield goes through several examples to try to explain how consciousness can relate to the physical brain. The first example looked at is children. Brains undergo a great deal of postnatal growth, yet we are born with most of our neurones. The growth occurs as connections between neurones increase. These connections strengthen and grow when exercised, like muscles. This is referred to as “neuronal plasticity”. Children are much more emotional than adults. Could this be because the emotional state of consciousness is more prominent due to the lack of neuronal connections in the brain? The increased emotional state of Alzheimer’s patients is also thought to be due to a decreased assembly of neurones.
Drugs are bridges between the physical events in the brain and the subjective inner brain. Opiods, heroine, cannabis and morphine all affect consciousness by targeting certain brain regions. But just how can simple molecules in drugs alleviate pain and cause euphoria? They have molecular targets in neurones which enable then to alter the ways in which neurones generate signals. It is not just drugs which have this affect. We have naturally occurring opiates called enkephalins. These are released when we eat chocolate, have tea or coffee or smoke as well as creating the phenomenon of ‘jogger’s high’. Even in a drug-free life, our brains are in a constant state of flux.

  In ‘The Private Life of the Brain’, Greenfield covers examples of other mental states such as dreaming, depression and schizophrenia which deepen her argument further than can be covered in a book review. I found this book incredibly interesting because it explains that confusing gap between psychology and neuroscience, and draws on a wide range of different examples. Although the brain obviously still remains to be an enigma, Greenfield’s theory is very convincing, and her argument is presented very clearly here. After reading, I could truly marvel at the human brain. How did we all evolve to have such intricate minds? Why do we have such colourful and complex personalities? How could the universe create a tool with which to understand itself?