[ad_1]
The octopus is an extraordinary creature – and not just because of its eight limbs, three hearts, blue blood, inkjet, camouflage ability, and the tragic fact that it dies after the coupling.
A study by Brazilian researchers published Thursday shows that this animal, already considered perhaps the most intelligent invertebrate, undergoes two major alternating sleep states eerily similar to humans – and it might even be dreaming.
The results, the researchers said, provide new evidence that the octopus possesses a complex and sophisticated neurobiology that underpins an equally sophisticated behavioral repertoire, while providing a broader insight into the evolution of sleep, a crucial biological function. .
Octopuses were previously known to sleep and change color while sleeping. In the new study, researchers observed a species called Octopus insularis in a lab. They found that these color changes are associated with two distinct sleep states: “calm sleep” and “active sleep”.
During “quiet sleep”, the octopus remains motionless, the skin pale and the eye pupils contracted to a slit. During “active sleep”, he dynamically changes the color and texture of his skin and moves both eyes while contracting his suction cups and body, with muscle twitching.
A repetitive cycle has been observed during sleep. “Quiet sleep” typically lasted about seven minutes. The “active sleep” that followed usually lasted less than a minute.
This cycle appears to be analogous, the researchers say, to the alternating states of “rapid eye movement,” or REM, and “non-rapid eye movement,” or non-REM, of states of sleep experienced by humans, as well as by humans. other mammals, birds and reptiles. .
Vivid dreaming occurs during REM sleep, as a person’s eyes move rapidly, breathing becomes irregular, heart rate increases, and muscles become paralyzed from dreaming. Non-REM sleep allows for deeper sleep and fewer dreams.
Lead author of the study, Sylvia Medeiros, said the results suggest octopuses may be dreaming or experiencing something similar.
“If octopuses are indeed dreaming, they are unlikely to experience complex symbolic plots the way we do,” said Medeiros, a doctoral student in neuroscience at the Brain Institute at the Federal University of Rio Grande do Norte.
“’Active sleep’ in the octopus has a very short duration, usually a few seconds to a minute. If during this state there is a dream going on, it should look more like small video clips, or even GIFs, ”added Medeiros.
Scientists are looking for a better understanding of the origins and evolution of sleep.
Because the last common ancestor of vertebrates, including humans, and cephalopods, including octopuses, lived over half a billion years ago, it seems unlikely that their similar sleep patterns were established before their evolutionary divergence, the researchers said.
This would mean, they added, that this similar sleep pattern emerged independently in the two groups, a phenomenon called “convergent evolution.”
“The investigation of sleep and dreaming in the octopus gives us a point of view for psychological and neurobiological comparison with vertebrates, as the octopus possesses several sophisticated cognitive characteristics that are only visible in certain vertebrate species but with a very different brain architecture, ”said study co-author Sidarta Ribeiro, founder of the Brain Institute.
Ribeiro noted that previous studies have shown that octopuses, with the most centralized nervous system of all invertebrates, possess exceptional learning abilities, including spatial and social learning, as well as problem-solving abilities. .
“Understanding how organisms as different as humans and octopuses can share fundamental traits such as the sleep cycle opens new avenues for the investigation of animal cognition and for understanding the general principles that have shaped brain design in these groups of highly intelligent animals, ”Medeiros said.
[ad_2]
Source link