Ecstasy can make octopuses more social, just like humans

Then she administered ecstasy to the animals. Again, there is no precedent, but researchers often anesthetize octopuses by dipping them in ethanol, a procedure without lasting side effects. Dölen and Edsinger immersed their octopus in a solution of MDMA, allowing them to absorb the drug through their gills. At first, they used too high a dose and the animals "panicked and made all these color changes," says Dölen. But once the team found a more appropriate dose, the animals behaved more calmly and wiser.

With ecstasy in their system, the five octopuses spent much more time in the company of the same man trapped than they had once fled. Even without a stopwatch, the change was obvious. Before the drug, they explored the room with the other octopus very tentatively. "They crashed against a wall, slowly extended an arm, touched the [other animal], and returned from the other side, "says Dölen. "But when they had MDMA, they had this very relaxed posture. They floated around, they wrapped their arms around the room, and they interacted with the other octopus in a much more fluid and generous way. They even exposed their [underside]where is their mouth, which is not something that octopuses usually do.

But most octopuses, with a few exceptions, are solitary and Jennifer Mather, from the University of Lethbridge, is not convinced that ecstasy makes them sociable. Instead, the drug could simply spoil their ability to detect the chemical clues of potential partners. "There is no proof that it's anything but an attraction," she says.

Harriet de Wit, from the University of Chicago, who has studied the effects of ecstasy on animals, has other concerns. "It's an innovative and exciting study," she says, but it's unfortunate that the duo always tested the octopuses first after a dunk in normal salt water and after an ecstasy bath. In pharmacology studies, scientists normally confuse the order in which animals receive the drug and saline control. Without this counterweight, it's hard to tell why octopuses behaved differently the second time: was it because of ecstasy or simply because they got acquainted with the arena, the toy plastic or the other octopus?

Dölen admits that the study is only a pilot project, with a very small sample. "Of course we would like other people to try to repeat it in a much larger group of animals," she says. "But we wanted to publish it because there are not really protocols for octopus medications or social testing with them." She hopes her findings will encourage more neuroscientists to study these seductive animals.

She is not the first to make such a call either. In 1964, the English zoologist J. Z. Young wrote a book entitled A model of the brain, in which he encouraged scientists to study the brain of a wide variety of species, including octopus. "We could say that the brain of the octopus is totally different from the human brain, but we need this synapse or this neurotransmitter," Dölen explains. "We could write a list of these minimal building blocks of complex behavior." And that's what she and Edsinger started doing.

They knew that ecstasy was working by having neurons release serotonin, a signaling chemical that affects our mood. The drug does this by sticking to a protein called the serotonin transporter, or SERT, which neurons normally use to aspirate the chemical. The presence of ecstasy reverses this flow, creating a massive discharge of serotonin that alters the mood.

Octopuses have their own version of SERT, and Dölen and Edsinger showed that it was only a 50% match with ours. Despite these differences, the specific bit of the protein that sticks to ecstasy is almost identical in both species, which is why the drug affects both. "We did not expect there to be such an overlap," says Dölen.

"Octopuses are really the best example of a second intelligence on Earth," says Robyn Crook, a neuroscientist at San Francisco State University. We shared a common ancestor with them about 800 million years ago, and their brains evolved independently of ours. And yet, Dölen's study has shown that our brain has some extreme similarities, from molecular level to behavior. According to Crook, this reinforces the idea: "There are not many ways to create a smart brain."