Octopuses have two main alternative sleep states – and dreams can be experienced

Octopus in Active Ng

This image shows an active octopus. Credit: Sylvia LS Maderos

Octopus is known for sleep and color whenever it does. Now, on March 25, 2021, a study published in the journal Eye Science Finds that this color change is characterized by two main alternative sleep patterns: an “active sleep sleep” stage and a “quiet sleep sleep” stage. The researchers say the findings have implications for the evolution of sleep and may indicate that it is possible for an octopus to experience something similar to dreams.

Scientists thought that only mammals and birds have two sleeps. More recently, it has been shown that some reptiles also show non-REM and REM sleep. In relation to octopuses, capillaries also reported REM-like sleep disorders.

“It made us wonder if we could even see evidence of two sleep states in an octopus,” says Cedarta Ribeiro, a senior author at the Brain Institute in Rio Grande do Norte, a federal university in Brazil. “Octopus is known to have the most central nervous system of any ultraviolet and is capable of higher learning.”

To find out, researchers captured video recordings of octopuses in the lab. They found that during the ‘quiet sleep’ the animals were pale and calm, the pale skin and pupils of the eyes were torn. It was a different story during ‘Active Sleep’. Animals dynamically change the color and texture of their skin. They also moved their eyes while contracting their sucker and body with muscular twitches.


“The more interesting thing about this is that this ‘sleep deprivation’ usually occurs after a long ‘quiet sleep’ – usually longer than 6 minutes – and its characteristic is periodic,” says Ribeiro.

The cycle will repeat at intervals of about 30-40 minutes. To establish that these states actually represent sleep, the researchers measured the excitation threshold of the octopus using visual and tactile stimulus tests. The results of those tests show that in both the ‘active’ and ‘quiet sleep’ states, the top octopus needs a stronger stimulus to respond to behavior than in the alert state. In other words, they were asleep.

In conclusion, top ectopus and sleep have interesting effects for sleep evolution. They also raise interesting new questions.

“The sleep observation observation in Octopus Insuluris, which resembles us, despite the evolutionary historical gap between cephalopods and vertebrates, with the earliest lineage variation about 50,000 million years ago,” says first author and graduate student Sylvia Madeiro. Brain organization.

“If in fact the state of two different states has evolved twice independently into vertebrates and invertebrates, what are the essential evolutionary pressures shaping this physiological process?” She asks. “Independent evolution in cephalopods of the same ‘active sleep’ as for REM sleep vertebrates may reflect the normal e-tidal property for central nervous systems reaching certain complexities.”

Madiros also says the findings increase the likelihood that the octopus will experience something similar to dreaming. “It is not possible to guarantee that they are dreaming because they cannot tell us, but our results suggest that octopuses may experience a similar state of REM sleep during ‘active sleep’, which is the stage in which humans dream the most. “If octopuses really do see, it’s not possible for them to experience complex symbolic plots like ours. Active octopuses have very little” sleep active sleep “time – usually a few seconds to a minute. In the meantime, if a dream is seen, it should be more like small video clips or GIFs. “

In a future study, researchers chose to record neural data from cephalopods to better understand what happens when sleep comes. They are also keen on the role of animals in metabolism, thinking and learning sleep.

“He speculates that, like humans, dreaming in octopuses can adapt to environmental challenges and promote learning,” says Ribeiro. “Do octopuses have nightmares? Can octopus dreams be written on their dynamic skin pattern? Can we learn to read their dreams by quantifying these changes? ”

References: “Replacement of the Cyclone of Sleep and Active Sleep in the Octopus” by Sylvia Lima de Souza Madiros, Miziara Marlene Matius de Pieva, Paulo Henrique Lopez, Wilfredo Blanco, Franઝois Dentos de Limao, Jeremio, Jeim. Tatina Silva Light and Cedarta Ribeiro, March 25, 2021, Eye Science.
DOI: 10.1016 / j.isci.2021.102223

The work was commissioned by the State University of Rio Grande do Norte (UERN), Cardenaso de Cerfecomento de Pesoal de Naval Superior (CAPES), by Cesel Nacelho Nacional de Disenvolvimento Ciencpio (C )niopacio) ) Center for Neuromathematics.