Octopuses: Much More Similar to Humans Than We Thought
Octopuses, those enigmatic creatures of the sea, continue to surprise us with their incredible abilities. While we already knew they were highly intelligent and capable of problem-solving, new research suggests that they also share a fundamental characteristic with humans: the ability to sleep and possibly dream.
Scientists have long believed that REM (rapid eye movement) sleep, the phase during which dreams occur, was exclusive to vertebrates. However, a recent study conducted by researchers at the Okinawa Institute of Science and Technology in Japan has shown that octopuses, as invertebrates, also exhibit REM-like sleep patterns, challenging what we thought we knew about sleep in different animal species.
In the study, the researchers observed octopuses during their sleep and noticed that they displayed two distinct phases: periods of quiet sleep, known as NREM (non-rapid eye movement) sleep, and bursts of neural activity that resembled the waking state, a characteristic of REM sleep. This finding makes octopuses the only known invertebrates to have two phases of sleep.
To confirm that the octopuses were indeed asleep, the researchers stimulated them while they were in a relaxed, lying position. The animals’ reaction to the stimulation was significantly slower during sleep compared to when they were awake. This validation allowed the researchers to proceed with their observations.
Using a technique called local field potential (LFP) recording, which tracks the electrical potential surrounding neurons, the researchers monitored the brain activity of the sleeping octopuses. They discovered that during NREM sleep, the brain activity was minimal, and any behavioral changes were subtle. However, during REM sleep, there was a remarkable increase in activity in the frontal and vertical lobes of the octopuses’ brains, regions that have similarities to the hippocampus and limbic lobe in humans.
During REM sleep, the researchers also observed a fascinating phenomenon: the octopuses’ skin changed color. Octopuses are well-known for their ability to camouflage by altering the pigments in their skin, and it is believed that their color changes during REM sleep could be related to dreaming and mental practice. Specifically, the researchers speculate that octopuses might be mentally rehearsing their camouflage techniques based on their past experiences.
This study highlights the surprising similarities between the sleeping patterns and neural activity of octopuses and humans. It raises questions about the evolution and function of sleep and dreams across different species. If the functions attributed to two-stage sleep, such as memory consolidation and emotional processing, are widespread among animals with complex cognitive abilities, we may need to reconsider our understanding of sleep and its significance beyond vertebrates.
Lead researcher Sam Reiter of the University of Okinawa intends to delve deeper into the sleeping octopus brain to unravel the mysteries of their dreams. The ultimate goal is to determine whether octopuses truly experience dreams during their REM sleep. While the answer remains elusive, this discovery moves us one step closer to understanding the remarkable creatures that have inhabited our oceans for millions of years.
The findings of this study not only expand our knowledge of sleep and neural function but also remind us of the incredible diversity and complexity of life on Earth. Octopuses, with their seemingly alien intelligence and abilities, challenge our preconceived notions about consciousness and what it means to be human. As we continue to peer into the depths of the ocean and unlock its secrets, we may find that we share more with these fascinating creatures than we ever imagined.
In a world full of wonders, the octopus once again mesmerizes us with its mysteries.
