'Very Intelligent Animals': Israeli Researchers Discover Octopuses' Impressive Cognitive Abilities

Some 275 million years ago a snail-like marine creature lost its cumbersome shell. In a rapid evolutionary process, it developed systems for propelling itself and, while developing excellent vision and a large brain, it was transformed from an innocent grazing snail into a sophisticated and efficient predator. That is how the octopuses as we know it, one of the most mysterious of beings, came to be – one that exhibits impressive cognitive abilities, but is totally different from any creature to which we commonly attribute intelligence.

A group of Israeli scientists, headed by Prof. Benny Hochner of the Department of Neurobiology at the Hebrew University's Silberman Institute of Life Sciences, in cooperation with Dr. Nir Nesher and Dr. Tal Shomrat of the Faculty of Marine Sciences at the Ruppin Academic Center, has been studying the intelligence of octopuses for almost 20 years. Among their most interesting discoveries, according to Hochner, is how these molluscs developed processes of learning and memory.

“They separated from us 500 million years ago," he explains. "We examined what happened in terms of evolution – asking whether various other species of animals developed the same solutions, or whether octopuses have different ones.”

A comprehensive study, published last month in the Journal of Morphology, entitled "Neurotransmission and neuromodulation systems in the learning and memory network of Octopus vulgaris," supports the researchers’ theory to the effect that the octopus’ intelligence has evolved in a manner that differs from what we know regarding mammals.

The group’s first study, in 2003, found that in the region of the vertical lobe of the octopus’ brain, which is organized neuroanatomically like the human hippocampus, there is a phenomenon called “long-term synaptic potentiation.” Its role: to mediate processes of learning and memory. That is, when the organism learns something, synaptic connections between specific neurons are strengthened for long time in its brain, and in that way memory is preserved.

In a series of studies, Hochner and his then-PhD student Dr. Naama Stern-Mentch, along with colleagues from the University of Florida, examined the neurotransmitters and substances called neuromodulators that are involved in the process of converting neural activity into long-term changes in the synaptic connections in octopuses.

It was found that as opposed to mammals, in which the process of associative learning is mediated by a special NMDA receptor, in octopuses it is mediated by a nitric-oxide molecule, which in humans is responsible mainly for the regulation of blood flow. “That means that in the course of evolution different solutions were found for coping with the same problem – how to mediate long-term synaptic potentiation,” Hochner says.

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The professor notes that the region of the octopus’ vertical lobe is organized in a relatively simple manner, but is very large: It has 25 million small nerve cells, compared to 40 million in the human hippocampus. The octopus has a total of 500 million nerve cells, similar to what dogs have, for example, but in the octopus two-thirds of those cells are found in its eight arms.

“They have a different and very efficient arrangement of their neural resources,” he concludes.

Presuming that processes like learning and memory are less complex in octopus brains than in humans, the researchers believe that if they succeed in understanding them, the information could be used to help design therapeutic and rehabilitation programs for humans with memory or learning issues. Such therapies may help people who have experienced serious cognitive decline do to degenerative conditions or old age – for example, through genetic therapies using the gene-editing technology CRISPR. “This is theoretically possible,” stresses Hochner.

Hochner cites the film “My Octopus Teacher” which depicts the bond that develops between a diver and a female octopus: “We experience the same thing. The octopuses come to us very frightened and withdrawn. It takes time for them to understand that we’re feeding them, and then they start to come out. They sit by the window and look at us. If they’re upset by something we are doing, they tend to spray water. These are very intelligent animals.”

An octopus’ average lifespan is only about a year. It's another mystery concerning the species: Why did natural selection produce such a short life cycle in these intelligent creatures, and how does it contribute to their survival?