I agree; Karl Friston's work is among the most interesting I have ever read, period. Interestingly, his 2009 paper (https://www.fil.ion.ucl.ac.uk/~karl/The%20free-energy%20prin...) / free-energy principle makes use of reinforcement learning, gradient descent, Markov blankets, Helmholtz machines, and other foundational tenets of modern machine learning ... In that regard, Geoff Hinton (a foundational figure in modern machine learning) overlapped with Friston while Hinton was in England at that point in his career.