In many ways it’s the ultimate question, what is consciousness? Since electrical recording, and later magnetic resonance imaging (MRI), of the brain became possible in the twentieth century, neuroscience has made such progress that it’s now possible to discuss the question in ways that would have seemed impossible then.

Photograph of Professor John Jefferys

I’ve come to discuss the ultimate question over a coffee with John Jefferys, Professor of Neuroscience, Department of Pharmacology and Senior Nicholas Kurti Fellow at Brasenose College.

He warns me that we’re not exactly going to nail the question just like that. It’s too large and consists of too many subsidiary questions. But, he suggests intriguingly, even reformulating the question in light of recent discoveries has enormous implications, because consciousness has to do with what makes humans distinctive, as a species and within evolution. As such, the question naturally flops over into other spheres of inquiry such as theology and philosophy – Jefferys is fast to mention David Chalmers, the Australian philosopher and former Rhodes Scholar who published an important book on the subject in 1996, The Conscious Mind.

In that book Chalmers, today the Director of a Centre for Consciousness at the Australian National University, wrote extensively about the failure of philosophers and scientists alike to properly address the problem of consciousness at all. He asked what the relationship is between brain and mind, for example, and he described it as a big, ‘hard’ problem of inquiry.

Jefferys is clear on that. He thinks the subject needs approaching through science, and firmly believes that consciousness depends on the brain, and will one day be defined – although it may take another century or more. Usually it is easy for us recognize when consciousness is lost, during sleep, or anaesthesia or some epileptic seizures, but saying what fundamentally is lost is difficult. But more prosaically we begin with me asking jokingly if the caffeine in my coffee will increase my consciousness. ‘There were drugs in the 1960s that were supposed to expand your consciousness,’ replies Jefferys, ‘ but that proved controversial.’ ‘On the other hand, caffeine increases awareness and awareness has a relationship to consciousness.’

He continues that consciousness has different levels. In medicine there is a way of scoring levels of coma resulting from brain trauma. Seen the other way round, a similar ‘spectrum’ approach can be taken to define different levels of consciousness. Sleeping is a classic example. You are not awake but in some phases of sleep your brain behaves as though it is. And after waking we experience different levels of wakefulness and drowsiness. Throw in memory and language, and you’re off down some deep and perplexing holes that have to do with humans. While it’s clear that animals and other living creatures are ‘conscious’ and may also have forms of communication if not exactly ‘language’, one of the things that makes humans unique is storing and building on the knowledge of previous generations. Our conversation takes place surrounded by thousands of books in the Weston library – Jefferys waves at them at one point.

For now, he says that neuroscience is ‘nibbling at the edges of this problem,’ but is under no illusions about how difficult it is. In very broad terms, Jefferys is willing to talk about what he calls ‘neural correlates’ of consciousness and its different facets, which include ideas such as recognition, awareness, introspection, memory and language. Neural correlates of consciousness are a major area for research, for instance by Christophe Koch and the late Nobel laureate, Francis Crick.

Pushing him for a summary, or ‘the nub of it’ as he puts it with a grin, Jefferys volunteers the word ‘awareness’, which is also where the Oxford English Dictionary weighs in, warning me though that consciousness and awareness exist inside each other, so the business of defining both becomes rather circular.

What would a scientific definition of consciousness resemble, I venture?

The answer is partly a matter of numbers, he says. There are believed to be approximately 86 billion brain cell bodies in the cerebral cortex of an average human being. Around them are trillions of axons connecting with neurons at junctions called synapses. Patterns of connections are as important as numbers. One exciting development is Integrated Information Theory, first advanced by Tonini and Koch. It aims to link the essential features of conscious experience to the physical brain using an information theory approach. IIT proposes a variable called ‘Phi’ after the Greek. If we could measure Phi we would have a definition of consciousness, and crucially for the science, we would be able to make testable predictions. But this measurement has proved extremely difficult in practice.

Jefferys, whose major hobby is deep sea diving (‘curiosity and exhilaration combined,’ he notes), has spent a professional lifetime staring deep into the murky waters of the workings of human and animal brains. At Oxford, at least five separate centres of excellence have now sprung up in the field, spanning the clinical treatment of brain maladies at one end of the spectrum, to the philosophy of mind at the other. As a result, the University is one of the leading clusters of neuroscience in 2017.

A colleague and other leading light in this field, also at Brasenose, is Chris Kennard, Emeritus Professor of Clinical Neurology. Kennard recently noted, ‘Our understanding of the brain has greatly increased over the last century, but if we liken our progress to scaling Mount Everest, due to the brain’s immense complexity, we are still only at base camp.’

As if to underline how complex it is, Jefferys notes that in one study some patients in a persistent vegetative state were nonetheless able to reply yes or no to questions, after a period of therapy, despite not being able to articulate those responses. The arising brain activity could only be shown through MRI scanning, which showed parts of the patients’ brains firing. He observes: ‘It’s scary – this was an unexpected result and huge implications for, say, euthanasia advocates.’

  • All these advances in knowledge are being celebrated in a marvelous little exhibition inside the Natural History Museum on Parks Road, called ‘Brain Diaries, Modern Neuroscience in Action’ – and the good news is that it runs until 1 January 2018.

John Jefferys, Professor of Neuroscience, Department of Pharmacology and Senior Nicholas Kurti Fellow at Brasenose College. John Jefferys studied Physiology at University College London, where he gained his BSc and PhD. He chose his courses and doctoral research topic because of his fascination with how brains worked. He has been able to develop his curiosity on brain function over his research posts in London, at the Royal Free Hospital, Institute of Neurology and, as a Wellcome Trust Senior Lecturer, at St Mary’s Hospital Medical School in Imperial College. In the mid-90’s he moved Birmingham University as Professor of Neuroscience, and then to Oxford in 2014. His major research focus is on epilepsy and related aspects of brain function, including fast oscillations thought to play roles in consciousness.