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todropscience · 11 months

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THIS OCTOPUS IS HAVING A NIGHTMARE, SCIENTISTS BELIEVE.

Sleep is a fundamental biological function present in all vertebrates and most invertebrates. Octopuses are really complex animals, displaying active and inactive sleep states similar to those of vertebrates. In particular, octopuses have active sleep states during which they display sequences of camouflage patterns, while remaining relatively quiet and unresponsive to external stimuli. Some scientists have speculated that these states could be analogous to dreaming in mammals.

Now, researchers have recorder what is believing an octopuses having nightmare. During a month, researchers recorded a male Brazilian reef octopus (Octopus insularis), and they detected four brief episodes were identified during which the octopus abruptly emerged from sleep, detached itself from its sleep position, and engaged in antipredator behaviors, despite no predator was present. The longest of these episodes resembled the species-typical response to a predatory attack, suggesting that the animal may have been responding to a negative episodic memory while sleeping.

However, these are just conjectures, as it is hard to be sure, according to scientists, who claim that more studies are needed to ensure that they really are nightmares.

Gif from video: Eric Ramos et al

Reference: Ramos et al., 2023. Abnormal behavioral episodes associated with sleep and quiescence in Octopus insularis: Possible nightmares in a cephalopod?. bioRxiv.

video can be seen here

#Octopus insularis #Octopus #Gif #animals #mollusc #biology #bioblr #biologyblr #science #marine science #sciblr #scienceblr

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kreuzaderny · 11 months

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Abnormal behavioral episodes associated with sleep and quiescence in Octopus insularis: Possible nightmares in a cephalopod?

This paper presents some unusual behaviors observed in one single specimen of O. insularis. While nothing can be concluded rigorously from such data, we share the data and our analysis with the community, in the hope that others will be on the lookout for such rare events. Sleep is a fundamental biological function that is present in all tested vertebrates and most invertebrates.

Cephalopods, such as octopuses, are cognitively complex animals that display active and inactive sleep states similar to those of vertebrates. In particular, octopuses have active sleep states during which they display sequences of camouflage patterns and modulation of basal rhythms, while remaining relatively unresponsive to outside stimuli. Some scientists have speculated that these states could be analogous to dreaming in mammals, involving episodic recall with a narrative structure. The convergent evolution of sleep in neurologically complex animals is a striking possibility, but its demonstration requires overcoming significant challenges. Towards this end, capturing abnormal sleep-associated episodes and other parasomnias in cephalopods can provide further insight into the biology of their sleep. This study reports abnormal behavioral episodes associated with transitions between activity states and sleep states observed in a male Octopus insularis. The study used continuous video monitoring to characterize the animal’s activity patterns and detect rare behavioral episodes. Over the course of a month, four brief episodes (duration range: 44-290 seconds) were identified during which the octopus abruptly emerged from quiescent or active sleep, detached itself from its sleep position, and engaged in antipredator and predatory behaviors (with no predator present). The longest of these episodes resembled the species-typical response to a predatory attack, suggesting that the animal may have been responding to a negative episodic memory or exhibiting a form of parasomnia. These findings, in conjunction with recent evidence for sleep in octopuses, highlight the complexity of possible sleep-associated behavioral episodes. Investigating sleep in invertebrates is crucial to understanding the evolution of sleep across distantly related species.

#sleep #neuroscience #brain #octopus #biology

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cipherinstars · 3 years

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[image id: a realistic style, plushie octopus insularis. It is orange with brown spots]

He is friend shaped :)

#octopus

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sciencespies · 3 years

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We have the first-ever confirmation of alternating sleep states in an octopus

https://sciencespies.com/nature/we-have-the-first-ever-confirmation-of-alternating-sleep-states-in-an-octopus/

We have the first-ever confirmation of alternating sleep states in an octopus

The flickering colors of a sleeping octopus seem to indicate something akin to an REM sleep state, scientists have found.

In fact, as octopuses snooze, they distinctly cycle between two major sleep states, quiet and active. This discovery suggests not only that an active sleep state evolved separately in vertebrates and cephalopods, but also that, just like terrestrial vertebrates, octopuses might be able to dream.

“The alternation of sleep states observed in the Octopus insularis seems quite similar to ours, despite the enormous evolutionary distance between cephalopods and vertebrates, with an early divergence of lineages around 500 million years ago,” said neuroscientist Sylvia Medeiros of the Federal University of Rio Grande do Norte in Brazil.

There’s a lot we don’t know about sleep. For a long time, scientists thought that only birds and mammals had sleep cycles, moving between active and quiet states – called REM (rapid eye movement) and non-REM sleep. REM sleep was only documented in reptiles for the first time five years ago.

Yet there had already been a hint that cyclic sleep was more widespread in the animal kingdom. In 2012, scientists found that cuttlefish (Sepia officinalis) “display a quiescent state with rapid eye movements, changes in body coloration and twitching of the arms, that is possibly analogous to REM sleep.”

“That led us to wonder whether we might see evidence of two sleep states in octopuses, too,” said neuroscientist Sidarta Ribeiro of the Federal University of Rio Grande do Norte.

“Octopuses have the most centralized nervous system of any invertebrate and are known to have a high learning capacity.”

The lucky octopus species chosen for the study was O. insularis, a species that lives off the coast of Brazil. Medeiros and her team collected four wild animals and, after a 10-day acclimation period, carefully recorded them sleeping.

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During the quiet state, the octopuses were pale and still; during the active state, however, they started to flicker and move. Their colors and textures changed rapidly, their eyes moved, their bodies twitched. The octopuses would cycle through these states at 30- to 40-minute intervals.

There was even a strange stage in which the octopuses’ bodies would be colored on one side, and pale on the other – all the while the animals remained perfectly peaceful.

The fact octopus colors and patterns appear to shift in their sleep has been observed, and even recorded before. Now we have compelling evidence of distinct states of activity that could be linked with forms of consciousness.

It was possible that one of the states wasn’t actually sleep at all, but could have been what the researchers term ��quiet alertness” – the octopuses were perfectly still, but awake and monitoring their surroundings. The researchers designed tests to rouse the octopuses to see how quickly they responded, one showing images on a screen, and another tapping the tank to induce vibrations.

In both states, the octopuses were much slower to respond to these stimuli than when they were known to be awake and alert, demonstrating that both states were indeed sleep.

(Medeiros et al., iScience, 2021)

The scientists speculated that the strange half-and-half stage may even be analogous to the unihemispheric slow-wave sleep seen in birds and aquatic mammals, in which only half the brain sleeps at a time. Further research will be needed to confirm this.

And the REM sleep could be a clue that octopuses may dream, just like other animals – although we may never know.

“It is not possible to affirm that they are dreaming because they cannot tell us that, but our results suggest that during ‘active sleep’ the octopus might experience a state analogous to REM sleep, which is the state during which humans dream the most,” Medeiros said.

“If octopuses indeed dream, it is unlikely that they experience complex symbolic plots like we do. ‘Active sleep’ in the octopus has a very short duration – typically from a few seconds to one minute. If during this state there is any dreaming going on, it should be more like small videoclips, or even gifs.”

The implications are fascinating. Octopuses are very, very different from humans. In fact, cephalopods have evolved vastly differently from pretty much every organism on Earth. They are pretty canny creatures, too, with incredible problem-solving skills – yet the way their intelligence works is, again, unlike pretty much any other organism.

We don’t really know for sure why we dream, but scientists believe it has something to do with the way the brain processes and stores memories. If that’s the case, it would make sense that many animals dream. Even so, with cephalopods so different from other animals, it’s pretty interesting that they could have evolved a very similar kind of sleep cycle.

“If in fact two different sleep states evolved twice independently in vertebrates and invertebrates, what are the essential evolutionary pressures shaping this physiological process?” Medeiros said.

“The independent evolution in cephalopods of an ‘active sleep’ analogous to vertebrate REM sleep may reflect an emerging property common to centralized nervous systems that reach a certain complexity.”

And don’t you wonder what an octopus sees when it dreams?

The research has been published in iScience.

#Nature

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yarrisharts · 5 years

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Coral Canyons Wall Dive - Identification Guide

I went through and marked off everything I included in my Coral Canyons plank! All the fish, corals, sponges, and invertebrates depicted are as accurate as my field guide, memory, and penmanship allowed for. Click through to see the whole list of 50 creatures that make up this plank (not counting our lucky diver)

Fish: Barracuda ( Sphyraena barracuda ) Black Durgon ( Melichthys niger ) Cubera Snapper ( Lutjanus cyanopterus ) Fairy Basslet ( Gramma loreto ) French Grunts ( Haemulon flavolineatum ) Green Moray ( Gymnothorax funebris ) Grey Angelfish ( Pomacanthus arcuatus ) Hogfish ( Lachnolaimus maximus ) Honeycomb Cowfish ( Acanthostracion polygonius ) Queen Angel ( Holacanthus ciliaris ) Roughtail Stingray ( Dasyatis centroura ) Sergeant Major Fish ( Abudefduf saxatilis ) Spotfin Butterflyfish ( Chaetodon ocellatus ) Stoplight Parrotfish initial phase ( Sparisoma viride ) Reef Squirrelfish ( Sargocentron coruscum ) Trumpetfish ( Aulostomus maculatus ) Whitetip Reef Shark ( Triaenodon obesus )

Invertebrates: Banded Coral Shrimp ( Stenopus hispidus ) Bluebell Tunicates ( Clavelina moluccensis ) Christmas Tree Worms ( Spirobranchus giganteus ) Comet Star ( Linckia guildingi ) Common Octopus ( Octopus vulgaris ) Coral Crab ( Carpilius corallinus ) Cushion Sea Star ( Oreaster reticulatus ) Fancy (Furry) Sea Cucumber ( Astichopus multifidus ) Flamingo Tongue ( Cyphoma gibbosum ) Longspined Urchin ( Diadema setosum ) Pencil Urchin ( Heterocentrotus mamillatus ) Reef Squid ( Sepioteuthis sepioidea ) Spiney Lobster ( Panulirus argus ) West Indian Sea Egg ( Tripneustes ventricosus )

Corals and Sponges: Barrel Sponge ( Xestospongia muta ) Blue Spiny Flower Coral ( Mussa angulosa ) Blushing Star Coral ( Stephanocoenia intersepts ) Branching Fire Coral ( Millepora alcicornis ) Branching Vase Sponges ( Callyspongia vaginalis ) Common Purple Seafans ( Gorgonia ventalina ) Elkhorn Coral ( Acropora palmata ) Various Encrusting Sponges Fire Coral ( Millepora ) Fused Staghorn Coral ( Acropora prolifera ) Lace Coral ( Stylaster roseus ) Lavendar Rope Sponge ( Niphates erecta ) Lettuce Coral ( Agaricia tenuifolia ) Long Sea Whips ( Ellisella elongata ) Oscarella ( Oscarella lobularis ) Pillar Coral ( Dendrogyra cylindricus ) Ridged Cactus Coral ( Mycetophyllia lamarckiana ) Symmetrical Brain Coral ( Diploria strigosa ) Yellow Tube Sponge ( Aplysina insularis )

#YarrishArts #caribbean coral reef diving #belize coral canyons scuba diving #stony corals #sponges #tunicates #invertebrates #cephalopods #fish

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