Mathematical law proposes a grand, unified theory of the brain
The Science and Technology Options Assessment (STOA) of the European Parliament organised a conference for Brain Awareness Week on 16 March 2010. As part of the event, Professor Karl Friston of the Wellcome Trust Centre for Neuroimaging was invited to present work which could potentially revolutionise brain research. Professor Friston has developed a mathematical law that approaches a grand unifying theory of how the brain works. A unifying theory with a simple equation to follow could potentially unravel the mysteries behind neurogenetic disorders, other diseases, and how we as humans process decision-making and learning. Around 35 percent of all diseases in humans find their origin in the brain. In Europe, the implications could revise how research on the brain is conducted. Last year alone, the EU spent over EUR 400 million to treat degenerative brain disease and disorders according to Paul Rübig, chairman of STOA. Understanding the brain helps researchers figure out how to treat disease. The benefits could not only help people but also target EU funding in brain research. For decades, scientists and researchers have been mapping out the brain through invasive dissection techniques to image processing and visualisation through the use of MRIs, x-rays and CAT scans. So while the physical representations of the areas of the human brain are now better understood, the functional integration in the human brain and the principles that underlie neuronal interactions remain a mystery. Or at least until Professor Friston developed his theory. 'It is a fundamental modelling of the brain. It is a dream come true for us because now we have a theory which we work with to see what is going on in the brain,' says Dr Thierry Metens from the Department of Radiology at Erasmus Hospital, Université libre de Bruxelles who attended the event. 'It was a Eureka moment,' says Professor Friston when he realised its full potential. 'Everything from action to perception was only to minimise free-energy. The challenge is to understand the coupling and integration of the brain area.' Professor Friston's work builds on the Bayesian brain theory where the brain functions on a principle of probabilities whereby it constantly makes predictions about the world and then updates them based on what it senses. Professor Friston's theory says that action and perception, according to the free-energy principle, leads to the optimisation of neuronal and neuromuscular activity to suppress prediction errors for free energy based on generative models of sensory data. Free energy is essentially a prediction error mechanism. This energy can be used to work within a system once that system's unused energy is removed. For example, the thousands of starling birds that flock and move about like a single mass do so by self-organising to minimise surprise. While the birds cannot measure the surprise they can measure the free-energy, which according to Friston's theory, is always greater than the surprise. The birds will therefore minimise free-energy so that small errors only lead to low surprises. Aside from action and perception, the minimisation of free-energy also has implications in learning, neurodevelopment and evolution. 'Homeostasis keeps use alive. We keep alive by minimising surprise in our environment,' adds Professor Friston. The conference was followed by a workshop on measuring brain function. Speakers at the workshop discussed recent advances in brain imaging, EU Directive 2004/40/EC and its relation to magnetic resonance imaging. STOA provides expert and independent assessments of scientific or technological options in the policy sectors to Committees at the European Parliament, and co-organised Brain Awareness Week in cooperation with the European Dana Alliance and the Belgian Brain Council.