The conclusions are drawn from a meta-analysis of previous studies and observations of the behavior of cephalopods.
Scientists from the American Geophysical Union analyzed previous work on the nervous system of octopuses, combined them with their own research and presented the results in a press release to speak at the Astrobiology Science Conference 2019, which is held from June 24 to 28 in Seattle, USA. …
This work is based on the conclusion that suckers on octopus tentacles can initiate actions in response to information they receive from the environment and coordinate their movements with neighboring suckers. This phenomenon is unique because it implies a completely different architecture of the nervous system than in vertebrates.
The evolution of octopuses took place after the animals split into vertebrates and invertebrates 500 million years ago. The vertebrate nervous system is concentrated in the brain and spinal cord. It is centralized and arranged according to the principle of ascending and descending connections. Therefore, the brain first receives information about the stimuli, and then, after processing the signals, gives a response to them. In octopuses, it is completely different.
Because cephalopods do not have a vertebral column, their ganglia (collections of nerve cells) are common throughout the body. In the process of evolution, large formations of ganglia turned into a brain, but at the same time their own architecture was preserved in the tentacles.
“The octopus's tentacles have a nerve ring that bypasses the brain, so they can share information with each other without communicating it to the brain. The latter does not know where the tentacles are in space, but the tentacles themselves are well aware of the position relative to each other, and this allows them to coordinate actions during movement,”said one of the authors of the article, Dominic Sivitilli.
The graphs represent the angular velocity of the tentacles over time. They indicate the synchrony or asynchronous pattern of movements between the tentacles.
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The researchers worked with two species of octopus: the giant octopus (Enteroctopus dofleini) and the red octopus (Octopus rubescens). They combined behavioral tracking and neural activity recording techniques to understand how octopus tentacles coordinate vast amounts of sensory and motor information for decision making. They gave the animals various items, such as cinder blocks and LEGO bricks, or launched them into mazes of food. The experiments confirmed the hypothesis of an independent nervous system of the tentacles and demonstrated how the ganglia make many small decisions.
Alexey Evglevsky