Scientists have managed to record the brain activity of octopuses without restricting their freedom of movement, a breakthrough reported by the Okinawa Institute of Science and Technology in Japan. The work adds a new dimension to comparative neurobiology by letting researchers observe natural behaviors while monitoring neural signals in real time.
Octopuses stand out as a remarkable model when exploring how the brain functions. They possess large brains, a highly distinctive body plan, and cognitive abilities that evolved along a path very different from that of vertebrates. Researchers emphasize that these features make octopuses a valuable point of comparison for mammals as scientists seek to understand the neural basis of learning and memory.
The challenge has long been that octopuses lack a skull to which electrodes can be affixed for encephalography, so previous recordings required immobilizing the animals. In response, the team devised a method that attaches compact, lightweight data loggers directly to the bodies of the octopuses. The devices were adapted to be waterproof and small enough to fit within the mantle without impeding movement. With batteries designed for operation in environments without air, the setup could sustain up to twelve hours of continuous recording.
In the initial phase, the researchers anesthetized three octopuses and placed the registrar in the mantle’s muscular wall cavity. Electrodes were positioned in the vertical lobe and the middle upper frontal lobe, areas believed to play a crucial role in visual learning and memory processes.
Once the surgery was finished, the octopuses were returned to an aquarium where their behavior was video recorded. The neural data were then synchronized with the footage to assess how brain activity aligned with observed actions. The early results demonstrated stable neural signals during natural behaviors, and the team plans to investigate further how specific brain patterns correspond to different behavioral states and learning tasks.
Beyond the immediate findings, the researchers hope this approach will open avenues to study the neural underpinnings of decision making, problem solving, and memory formation in a non-vertebrate model. By capturing brain activity in freely moving animals, the work aims to enrich our understanding of cognitive evolution and the diversity of neural strategies across species.