Structure Guides Function: How Brains Do More Than Computation

A central theme in Jon Kaas’ research, celebrated in this issue, is the relationship between brain structure and function. As a tribute, we examine how certain neuroanatomical structures enable functions that go beyond classical computations instantiated on conventional computers. Specifically, we argue that biological neurons exploit coincident input detection to realize more-than-pairwise, higher-order operations that cannot be reduced to pairwise interactions. Such processes can be simulated on conventional computers, but cannot be physically instantiated in their hardware. Pairwise statistics systematically miss these effects. To formally capture and analyze these higher-order neural interactions, we advocate for an extension of graph-based models of neuronal connectivity to hypergraphs. We conclude that, while brain function is sometimes likened to that of a conventional computer, brains can instantiate information processing beyond the limits of classical computation. In this sense, brains do not just “compute more”; brains do more than just compute.