TY - JOUR T1 - An Option Space for Early Neural Evolution JF - bioRxiv DO - 10.1101/027425 SP - 027425 AU - Gáspár Jékely AU - Fred Keijzer AU - Peter Godfrey Smith Y1 - 2015/01/01 UR - http://biorxiv.org/content/early/2015/09/28/027425.abstract N2 - The origin of nervous systems has traditionally been discussed within two conceptual frameworks. Input-output models stress the sensory-motor aspects of nervous systems, while internal coordination models emphasize the role of nervous systems in coordinating multicellular activity, especially muscle-based motility. Here we consider both frameworks and apply them to describe aspects of each of three main groups of phenomena that nervous systems control: behavior, physiology and development. We argue that both frameworks and all three aspects of nervous system function need to be considered for a comprehensive discussion of nervous system origins. This broad mapping of the option space enables an overview of the many influences and constraints that may have played a role in the evolution of the first nervous systems. ER -