Los octopuses they are a complete mystery: they are capable of solving very complicated problems, they have nervous systems as evolved as those of mammals, or their biochemistry is so different from everything else that some have proposed that they arrived from space. Now, a new study published in the journal ‘Current Biology’ has added a new question: after monitoring the brain activity of these cephalopods, they have found signals that have no explanation.
The authors managed to enter the mind of the octopus after implanting electrodes under their skin that could record up toto 12 hours of brain activity. What exactly the recordings mean has yet to be figured out, but the research demonstrates a first step toward understanding the strange and intricate brains of these unique animals.
“If we want to understand how the brain works, octopuses are the perfect animal to study compared to mammals,” he explains. Tamar Gutnick, researcher at the Okinawa Institute of Science and Technology (Japan) and the University of Naples Federico II (Italy). “They have a large brain, an incredibly unique body, and advanced cognitive abilities that have developed in completely different ways than vertebrates.”
How to put the ‘collar’ on the octopus
Octopuses are highly intelligent and extremely curious animals. Plus, their eight fully movable arms give them reaching and handling abilities unrivaled in the animal kingdom. That makes it difficult to put any type of device on your skin. “If we tried to connect wires to them, they would rip it off right away,” Gutnick explains, “so we needed a way to get the equipment completely out of their reach, by getting it under their skin.”
Thus, the team looked at the electrodes and devices used to track the brain activity of birds in flight. These devices are often protected by a hard plastic waterproof casing that has a relatively large profile and is therefore not suitable for implantation in octopuses, so the team developed a streamlined casing of plastic tubes.
They selected for their work three octopuses of the species Octopus cyanea, also known as the great blue octopus; a large octopus with a cavity within the mantle – the domed octopus ‘head’ – into which the device could be accommodated. The researchers implanted the electrodes inside each previously anesthetized octopus directly into the upper vertical and median frontal lobes. Then they were connected to the mantle of the octopus, where the recording device was located, which had a battery to record the animal’s brain activity for 12 hours without interruption.
Once the equipment was inserted, the authors returned the octopuses to their tanks, which after a while woke up and returned to their normal activity -although this time, monitored-. Video cameras were also installed to record what they were doing and then compare the brain activity with the behavior of each octopus.
Once the recordings were complete, the researchers euthanized the octopuses and retrieved the devices. They identified several long-lasting patterns of brain activity, including some similar to those seen in mammals. Other patterns, however, are nothing like what we know of other brains.
Unanswered
What they mean is a mystery. The patterns could not be linked to any of the behaviors seen in the videos. But mysterious as it may seem, the authors stress that it shouldn’t be a big surprise: The brain regions where the electrodes were placed are associated with learning and memory, and the octopuses were not required to perform any memory tasks. learning or memory during the experiment.
That could be the focus of future experiments, perhaps on a broader range of subjects and species. “This is a really fundamental study, but it’s only the first step,” says the zoologist. Michael Cuba, formerly of OIST and now at the University of Naples Federico II. “Octopuses are highly intelligent, but right now we know very little about how their brains work. This technique means that we now have the ability to look inside their brain as they perform specific tasks. It’s really exciting”.