Karl Friston is Professor of Neurology at University College London. He is a theoretical neuroscientist and authority on brain imaging. Although he trained in psychiatry, his revolutionary impact on studies of the brain derives from his inventive use of probability theory to analyze neural imaging data. He invented statistical parametric mapping, voxel-based morphometry, and dynamic causal modeling. These contributions were motivated by schizophrenia research and theoretical studies of value-learning, formulated as the disconnection hypothesis of schizophrenia. Friston works on models of functional integration in the human brain and the principles that underlie neuronal interactions. His main contribution to theoretical neurobiology is a free-energy principle for action and perception (active inference). He was elected a fellow of the Royal Society in 2006 and became a fellow of the Royal Society of Biology in 2012. He was the 2016 recipient of the Charles Branch Award for unparalleled breakthroughs in brain research and the Glass Brain Award, a lifetime achievement award in the field of human brain mapping. He holds honorary doctorates from the University of Zurich and Radboud University.
Abstract: This overview of the free energy principle offers an account of embodied exchange with the world that associates neuronal operations with actively inferring the causes of our sensations. Its agenda is to link formal (mathematical) descriptions of dynamical systems to a description of perception in terms of beliefs and goals. The argument has two parts: the first calls on the lawful dynamics of any (weakly mixing) system — from a single cell to a human brain. These lawful dynamics suggest that (internal) states can be interpreted as modeling or predicting the (external) causes of sensory fluctuations. In other words, if a system exists, its internal states must encode probabilistic beliefs about external states. Heuristically, this means that if I exist (am) then I must have beliefs (think). The second part of the argument is that the only tenable beliefs I can entertain about myself are that I exist. This may seem rather obvious; however, it transpires that this is equivalent to believing that the world — and the way it is sampled — will resolve uncertainty about the causes of sensations. We will consider the implications for functional anatomy, in terms of predictive coding and hierarchical architectures, and conclude by looking at the epistemic, self-evidencing behavior that emerges — using simulations of active inference.
This Provost’s Lecture will be held on Thursday, April 25, at 4 pm in the Charles B. Wang Center, Lecture Hall 2.
Co-Sponsors: Institute for Advanced Computational Science, Center for Neural Circuit Dynamics, Department of Neurobiology and Behavior