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bioRxiv · 10.1101/2023.05.04.538973

Sleep is required for neural network plasticity in the jellyfish Cassiopea

Abrams, M. J.·Zhang, L.·von Emster, K.·Lee, B. H.·Zeigler, H.·Jain, T.·Jafri, A.·Chen, Z.·Harland, R. J.
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Abstract

Sleep in animals plays roles that appear specific to the brain, including synaptic homeostasis [1], neurotransmitter regulation [2], cellular repair [3], memory consolidation [4], and neural plasticity [5,6]. Would any of these functions of sleep be relevant to an animal without a brain? The upside-down jellyfish Cassiopea xamachana, like other cnidarians, lacks a centralized nervous system, yet the animal sleeps [7]. By tracking the propensity of the radially spaced ganglia to initiate muscle contractions over several days we determined how neural activity changes between sleep and wake in a decentralized nervous system. Ganglia-network sleep/ wake activity patterns range from being highly specialized to a few ganglia, to being completely unspecialized. Ganglia specialization also changes over time, indicating a high degree of plasticity in the neural network. The ganglia that lead activity can persist or switch between sleep/wake transitions, signifying a level of local control of the behavioral state in a decentralized nervous system. Following sleep deprivation, ganglia usage becomes far more sleep specialized, demonstrating reduced network plasticity. Together, these findings identify a novel behavioral control system that is decentralized and yet displays temporal specialization and centralization, and show a role for sleep in maintaining neural network plasticity, revealing a conserved function of sleep in this brain-less animal.

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Abrams, M. J., Zhang, L., von Emster, K., Lee, B. H., Zeigler, H., Jain, T., Jafri, A., Chen, Z., Harland, R. J.. 2023-05-05. Sleep is required for neural network plasticity in the jellyfish Cassiopea. https://doi.org/10.1101/2023.05.04.538973

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