Researchers found octopuses share parts of an ancient messaging system involved in social behaviors with humans.
Octopuses are smart. They open jars, steal fish and high-five each other.
Though interactive, they’re generally asocial, and temperamental, with unique behavior patterns, like those shown by Otto, who caused blackouts at a German aquarium and Inky, who famously escaped a tank in New Zealand. They learn through experience and observation, forming lasting memories with brainlike bundles of hundreds of millions of neurons in each arm and a centralized bundle in the middle.
A desire to understand the evolutionary underpinnings of this brain power led scientists to give octopuses ecstasy. Yes ecstasy — molly, E, MDMA, the party drug, which in humans reduces fear and inhibition, induces feelings of empathy, distorts time and helps people dance to electronic music all night.
And under the influence of MDMA, the researchers report in a paper published earlier this month in Current Biology, asocial octopuses seemed to become more social.
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“Even though octopuses look like they come from outer space, they’re actually not that different from us,” said Gül Dölen, a neuroscientist at Johns Hopkins University School of Medicine who led the study with Eric Edsinger, an octopus researcher at Marine Biological Laboratory in Woods Hole.
They also found that humans and octopuses share parts of an ancient messaging system involved in social behaviors, one enhanced by the presence of MDMA in both animals. These shared linages may have been conserved to reduce fear and enable social behaviors. And although preliminary, the authors think octopuses present a promising model for studying MDMA’s effects on the human brain, treating PTSD and better understanding how the brain evolved to conjure social behaviors.
MDMA helps release, among other chemicals, serotonin. That ancient molecule is involved in regulating mood and social behaviors in invertebrates like locusts as well as vertebrates, like fish, insects, dogs and humans.
For Dölen, who is interested in evolution of social behavior, the octopus offered an interesting test of MDMA and serotonin, because it is separated by 500 million years of evolution from humans, but also has complex behavior.
Octopuses suspend their aggression for a few minutes to mate, perhaps accessing an otherwise switched-off neural signaling system — potentially similar to the one that helps humans behave socially, she reasoned. And any similarities in octopus and human genetic code related to this system could help her understand how the brain — down to its tiniest bits — evolved to govern social behaviors.
Like a wedge in Pac-Man’s mouth, MDMA fits inside a protein that moves serotonin in and out of neurons. The drug eventually causes a flood of serotonin between synapses, increasing its signals. When the researchers compared the genome of the California two-spot octopus (Octopus bimaculoides) to those of other animals, they discovered humans and octopuses could both make this protein, and it was nearly 100 percent similar at that special Pac-Man spot.
But would that protein on ecstasy also make octopuses social?
They put the octopuses in the center of a three-chambered tank where they could explore a Star Wars figurine on one side or another octopus on the other (it was contained beneath an overturned orchid pot with holes, in case the MDMA hadn’t worked and violence ensued).
Undosed, octopuses of either sex spent more time with the toy than the other octopus (if it was a male; they seemed less concerned when it was female).
But after soaking in low-dose MDMA-laced baths, the octopuses seemed to relax. They spent more time with the male octopuses on the other side of the tank.
They also hugged the pot with several arms, showing off their ventral ends, or mouths, almost like how the Larger Pacific Striped Octopus, the only known social octopus species, mates beak to beak in an eight-armed hug.
Though they tested only a few octopuses and MDMA likely acts on more molecules than serotonin, Charles Nichols, a pharmacologist at the Louisiana State University School of Medicine, was impressed: “I’ve been giving psychedelics to fruit flies for years in my lab, but had yet to have seen one given to an octopus.”
And David Nichols, his father who pioneered studies of MDMA for therapy, wonders how the drug might help untangle the fear circuitry in octopuses: “Connecting the dots in the octopus may lead to scientists being able to connect the dots, so to speak, in other species, including man,” David Nichols said.
Though just beginning, Dölen is hopeful: “We need to be taking full advantage of these compounds to see what they’re doing to the brain,” she said.
She added that when the octopuses came down from their serotonin highs, they acted completely normal — for an octopus.