Podcast with Ton Coolen on immune networks and neural networks

What if the mathematics behind neural networks could unlock the secrets of the immune system? Physicist Ton Coolen reveals how techniques from statistical mechanics, originally developed for obscure magnetic materials, now expose deep structural parallels between how brains store memories and how immune systems learn to fight disease. Subscribe for more from the Convergent Science Network podcast series. Ton Coolen joins Paul Verschure and Tony Prescott to explain how a collaboration with Italian researchers led him to apply finite connectivity analysis, a mathematical framework only available since around 2000, to models of immune network function. The resulting models map directly onto Hopfield-type attractor networks from neural network theory, with cytokine signaling playing the role of synaptic connections and B-cell receptor evolution functioning as a rewiring mechanism. The conversation traces how applied problems in biology have driven fundamental advances in theoretical physics, inverting the usual relationship between basic and applied science. The discussion explores what the immune system can teach neuroscience about memory and learning. Unlike neural networks where few patterns with many bits are stored, immune networks store many patterns with few bits each , a regime that demands entirely different mathematical treatment. Coolen argues that biological heterogeneity, shaped by evolution rather than randomness, represents a fundamental challenge that standard physical methods cannot handle, pointing toward a new class of problems at the boundary of physics and biology. Key topics include the mathematical parallels between Hopfield networks and immune models, why equilibrium statistical mechanics fails for living systems, how hypermutation and selection function as a learning algorithm, the unsolved problem of immune memory, and the tantalizing possibility that the nervous system anticipates and regulates immune responses through brain-immune coupling. Part of the Convergent Science Network podcast series from the BCBT Summer School.