DOI: 10.5061/dryad.pv814j1
title: Data from: The function of the ophiuroid nerve ring: how a decentralized nervous system controls coordinated locomotion

description: 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.
description: Specimen 2
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