Does a Self-Similarity Logic Shape the Organization of the Nervous System?

From the morphological point of view, the nervous system exhibits a fractal, self-similar geometry at various levels of observations, from single cells up to cell networks. From the functional point of view, it is characterized by a hierarchic organization in which self-similar structures (networks) of different miniaturizations are nested within each other. In particular, neuronal networks, interconnected to form neuronal systems, are formed by neurons, which operate thanks to their molecular networks, mainly having proteins as components that via protein–protein interactions can be assembled in multimeric complexes working as micro-devices. On this basis, the term “self-similarity logic” was introduced to describe a nested organization where at the various levels almost the same rules (logic) to perform operations are used. Self-similarity and self-similarity logic appear intimately linked to the biophysical evidence for the nervous system being a pattern-forming system that can switch fl exibly from one coherent state to another. Thus, they can represent key concepts to describe its complexity and its concerted, holistic behavior.