Scientists have successfully recorded brain activity from freely moving octopuses.
This is a scientific breakthrough as their soft bodies have, to date, made this near impossible.
“Measuring the brainwaves of octopuses has proven a real technical challenge. Unlike vertebrates, octopuses are soft-bodied, so they have no skull to anchor the recording equipment onto, to prevent it being removed,” according to the group of international researchers whose paper was published this month in Current Biology.
The scientists implanted electrodes and a data logger directly into the creatures, and have described their work as a “critical step forward in figuring out how octopuses’ brains control their behaviour”.
It could provide clues to the common principles needed for intelligence and cognition to occur.
Dr Tamar Gutnick, who formerly worked at the Okinawa Institute of Science and Technology that led the study, said: “Octopuses have eight powerful and ultra-flexible arms, which can reach absolutely anywhere on their body. If we tried to attach wires to them, they would immediately rip them off, so we needed a way of getting the equipment completely out of their reach, by placing it under their skin.”
The researchers settled on small and lightweight data loggers as the solution, originally designed to track the brain activity of birds during flight.
The team adapted the devices to make them waterproof but small enough to fit inside the octopuses. The batteries, which needed to work in a low-air environment, allowed up to 12 hours of continuous recording.
After the devices were surgically implanted, the octopuses were returned to their home tank and monitored by video.
After five minutes, they had recovered and spent the next 12 hours sleeping, eating and moving about their tank as their brain activity was recorded.
The logger and electrodes were then removed from the octopuses and the data synchronised to the video.
The researchers identified several distinct patterns of brain activity, some of which were similar in size and shape to those seen in mammals, while others were long-lasting, slow oscillations that had not been described before.
But beyond providing clues to how intelligence in general works, an expert at the Neuroscience Institute at the University of Cape Town, Dr Hayley Tomes, hopes this will increase awareness of the sentience of other creatures.
“The study might serve to help humans become more aware of the sentience and intelligence of these and other creatures. I don’t think scientific findings need to specifically relate to humans to be important — we as humans tend to be quite human-centric, but understanding that intelligence exists in other forms [no less important] might be exactly the kind of paradigm shift needed to bring humans more in line with nature. This is sorely needed in a world in which we have caused so much habitat destruction and species extinction,” she said.
She also points out that the study has its limits in terms of shedding light on human intelligence.
“This study is an important starting point for getting to grips with how an octopus’ brain functions, and future experiments are likely to yield significant differences when compared to human brains but will also likely show the neural basis of their clear intelligence.
“They only looked at brain activity in response to the categories of general motion, locomotion, sleep, cleaning or grooming and tactile exploration. Not higher order functions like executive planning, learning and memory [things more easily classed as measures of intelligence],” she said.
She said researchers stated in the article that the brain area measured is associated with learning and memory, and so to really explore the brain activity of this area, they would need to give the octopus learning/memory-related tasks, which they aim to do in the future.
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