Data from: The function of the ophiuroid nerve ring: how a decentralized nervous system controls coordinated locomotion

Echinoderms lack a centralized nervous control system yet each extant
echinoderm class has evolved unique and effective strategies for
locomotion. Brittle stars (Ophiuroidea) stride swiftly over the seafloor
by coordinating motions of their five muscular arms. Their arms consist of
many repeating segments, requiring them to use a complex control system to
coordinate motions among segments and between arms. We conducted in vivo
experiments with brittle stars to analyze the functional role of the nerve
ring, which connects the nerves in each arm. These experiments were
designed to determine how the ophiuroid nervous system performs complex
decision-making and locomotory actions under decentralized control. Our
results show that brittle star arms must be connected by the nerve ring
for coordinated locomotion, but information can travel bidirectionally
around the nerve ring so that it circumvents the severance. Evidence
presented indicates that ophiuroids rely on adjacent nerve ring
connections for sustained periodic movements. The number of arms connected
via the nerve ring is correlated positively with the likelihood that the
animal will show coordinated locomotion, indicating that integrated nerve
ring tissue is critical for control. The results of the experiments should
provide a basis for the advancement of complex artificial decentralized
systems.