Fundamental aspects of functional circuit growth will be investigated in A1 by considering Hydra. The focus lies on studying the structure formation of the nerve net as well as the emergence of light-modulated SBCs with respect to Hydra’s ontogenesis. Here, light-modulated SBCs can be understood as an elementary sensory information processing. The investigations will be carried out both experimentally and computationally by a circuit-related software emulator, where the latter supports the specification of electrical design.