Explaining Consciousness as Neural Dynamical Complexity

A scientific account of consciousness is a key objective for 21st century science. A large array of consciousness-relevant empirical data has been gathered from rapidly advancing brain imaging technology, and the beginnings of theories accounting for aspects of consciousness have been formed. There is now reason to believe that we are on the verge of a major breakthrough in our understanding of what is special about the particular types of brain activity and brain tasks that are associated with consciousness.

It appears that consciousness involves a precisely balanced amount of communication between the different brain regions. Too much shouting and no region can get on with processing its specifically assigned job. Too little and nothing will be tied together into a unified broadcast across the whole brain. If there is a careful balance between regional segregation and global integration of information, then the globally broadcast content will give rise to a conscious experience.

This project will attempt to measure consciousness by describing this subtle property in mathematical models of brain activity. It aims to predict a person's level of consciousness by analysing brain data alone, e.g. to distinguish between whether they are fully awake, drowsy, or in deep sleep. The project will take advantage of state-of-the-art data, including `intracranial' recordings from surgically implanted electrodes that have, for medical reasons, been placed either on the brain's surface, or deep inside the brain. Analyses will be based on recordings from groups of electrodes that detect electric fields generated by the activity of large populations of neurons. Computer simulations will help identify the signatures of consciousness-related activity in the signals picked up by electrodes. A combination of new mathematical models, measures and statistical techniques will ensure that inferences about consciousness are made reliably based on properties of the data, and not from random fluctuations in activity or by inaccuracies in measurement.

Consciousness science is particularly exciting because what is uncovered has profound implications for our place in nature and for our understanding of our very selves. At the practical level, having a reliable measure of conscious level would be extremely attractive in the clinic. There are scenarios in which traditional assessments of consciousness based on patient behaviour are unreliable. After a serious accident or a stroke, patients can be left in a condition in which they are completely unresponsive, yet could still be conscious and unable to communicate. This research will help inform diagnoses of patients suffering from such a disorder of consciousness, and guide ethical decisions on their treatment. This research will also find applications in psychiatry, since some mental illnesses can be considered as disorders of consciousness. Understanding the complex neural mechanisms of consciousness will open up new avenues for diagnosing mental illness and for treatment of mental suffering.

This project will provide a new way of looking at `complex' systems broadly conceived as any entity that consists of many components that interact in such a way that the whole is greater than the sum of the parts. The mathematical and statistical tools developed will therefore have potential for application far beyond the study of the human brain, for example, to information technology, traffic control, climate change and finance, to name just a few domains in which complex systems arise.

It is an exciting time for the field of consciousness science. Advances in brain imaging technology are allowing increasingly detailed data to be gathered, and new inter-disciplinary approaches are yielding intriguing new ideas. That the field is ripe for progress, and the fact that the questions it poses are so fundamental, means that there is potential for huge impact in multiple sectors from this research.

In the academic sector this work will impact highly on the cognitive and computational neuroscience of consciousness. There is a clear need for a unifying theoretical framework within which to process rapidly accumulating and increasingly more detailed empirical data pertaining to consciousness. This proposal represents a unique package of mathematical yet empirically grounded research to build upon and unify several distinct strands of theory and provide new tools for data-analysis.

Beyond consciousness, the work will broadly impact cognitive neuroscience by furthering the state-of-the-art in assessing directed interactions between brain regions from electrophysiological data. Since it is becoming increasingly acknowledged that all cognitive brain processes rely on dynamical inter-regional interactions, any advances in measuring these will be hugely beneficial.

New algorithms for measuring complexity will impact on the study, design, engineering and control of all kinds of complex systems, e.g. computers, traffic, financial systems, in academia and in industry.

Analysing metacognition (knowledge of perception) is important to many areas of psychology. My rigorous approach to this is already finding application to behavioural studies at Sussex on artificial grammar learning, and interoception and emotion. The proposed development of software for analysing metacognition will ensure continued and expanded impact of my research in this area.

There is potential for substantial impact in the clinic. After traumatic brain injury from a serious accident or a stroke, patients can be left in an unresponsive state, yet could still be conscious and unable to communicate. Critically, such patients may appear to go through wake-sleep cycles, whilst still failing standard tests of conscious awareness based on sustained non-reflexive behavioural responses. By enabling us to better assess the presence and level of consciousness from brain activity, this research could help develop new diagnostic methods for use on patients suffering from such serious disorders of consciousness, and ultimately help guide ethical decisions on their treatment. Similarly, this research could help the development of new technology for better monitoring of anaesthetic depth during surgery. There are occasions when it becomes difficult to assess anaesthetic depth, and advances in monitoring would enable smaller doses of anaesthetic to be used, leading to a decrease in the sometimes severe side-effects of anaesthesia, and a drop in the number of cases of patients being consciously aware during surgery.

In psychiatry, many mental illnesses are increasingly being considered as disorders of consciousness and/or disturbances in brain connectivity. By enhancing our understanding of the neural mechanisms and connectivity underlying consciousness, this research will open up new pathways for diagnosing mental illness and for treatment of mental suffering.

Public impact will be especially high for this research. Consciousness research strikes at the essence of the way we view our very selves, via its profound implications for our place in nature. Journalists in all branches of the media are aware of the blossoming of a new science of consciousness, as testified by the increasing number of articles and radio and television shows dedicated to the subject. The media are highly aware of the Sackler Centre for Consciousness Science as a new and unique venue for research at the frontier; e.g., there have been recent visits by New Scientist and the BBC.