Karl Friston

Karl John Friston FRS FMedSci FRSB (born 12 July 1959) is a British neuroscientist and theoretician at University College London. He is renowned for pioneering statistical parametric mapping, voxel-based morphometry, and dynamic causal modelling, which have become global standards in brain imaging. Friston is also the originator of the free energy principle and active inference, influential theories of brain function that unify perception, action, and learning within a Bayesian framework.

Educated at Cambridge (natural sciences, physics, psychology) and King's College Hospital (medicine), he trained in psychiatry under the Oxford University scheme before joining UCL, where he became Professor of Neuroscience and Scientific Director of the Wellcome Trust Centre for Neuroimaging. His research, initially motivated by schizophrenia, has expanded to encompass neuroimaging, theoretical neurobiology, and systems biology, including applications to epidemiological modelling during the COVID-19 pandemic.

Friston is among the most cited scientists in the world, ranked the top neuroscientist globally by Semantic Scholar in 2016, with an h-index above 280. His achievements have been recognised by numerous honours, including election to the Royal Society (2006), the Academy of Medical Sciences, the Royal Society of Biology, EMBO, and the Academia Europaea, alongside awards such as the Minerva Golden Brain Award, the Weldon Memorial Prize, and the Glass Brain Award.