The cephalopod brain: Motion control, learning, and cognition

Outgrowing their molluscan ancestors coleoid cephalopods have developed a remarkable complexity of behaviors and the underlying nervous system that controls them. Like in other phyla, such as teleost fish, cephalopods follow a trend for cephalization the concentration and evolution of a head holding acute sense organs an a highly concentrated central brain. The brains of cephalopods developed many de novo structures termed lobules by previous researchers. On the other hand the peripheral nervous system, having to control the complex motor output in its muscular hydrostat body has retained a remarkable size and level of independence. The flexible muscular hydrostat movement system theoretically has unlimited degrees of freedom, and octopuses are models for “soft bodied” robots. The decentralized nervous system, particularly in the arms of octopuses, results in decision making at many levels. Cephalopods developed a camouflage/signaling system in their skin that is unmatched in complexity and speed. This gives cephalopods to on one hand communicate with conspecifics and on the other hand to use a system of active camouflage to disappear from the sight of predators and prey alike. Modern cephalopods represent an alternative model to the vertebrates for the evolution of complex brains and high intelligence, which has as yet been only partly explored.