Octopus sleep is surprisingly similar to humans and contains a wake-like stage

[Kamaji]

Octopus sleep is surprisingly similar to humans and contains a wake-like stage

Date:  June 28, 2023
Source:  Okinawa Institute of Science and Technology (OIST) Graduate University
Summary:  Researchers have closely examined the brain activity and skin patterning in octopuses (Octopus laqueus) during active sleep and discovered that it closely resembles neural activity and skin patterning behavior seen when awake.

When octopuses sleep, their quiet periods of slumber are punctuated by short bursts of frenzied activity. Their arms and eyes twitch, their breathing rate quickens, and their skin flashes with vibrant colors.

Now, researchers from the Okinawa Institute of Science and Technology (OIST), in collaboration with the University of Washington, have closely examined the brain activity and skin patterning in octopuses (Octopus laqueus) during this active period of sleep and discovered that they closely resemble neural activity and skin patterning behavior seen when awake. Wake-like activity also occurs during rapid eye movement (REM) sleep in mammals -- the phase in which most dreams occur.

The study, published 28 June in Nature, highlights the remarkable similarities between the sleeping behavior of octopuses and humans and provides fascinating insights about the origin and function of sleep.

"All animals seem to show some form of sleep, even simple animals like jellyfish and fruit flies. But for a long time, only vertebrates were known to cycle between two different sleep stages," said senior author, Professor Sam Reiter, who leads the Computational Neuroethology Unit at OIST.

"The fact that two-stage sleep has independently evolved in distantly related creatures, like octopuses, which have large but completely different brain structures from vertebrates, suggests that possessing an active, wake-like stage may be a general feature of complex cognition," said author Dr. Leenoy Meshulam, a statistical physicist at the University of Washington, who helped design the research during her three month stay at OIST as a guest of the Theoretical Sciences Visiting Program.

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Source:  https://www.sciencedaily.com/releases/2023/06/230628130356.htm