Scientists Grow Human Mini-Brains in Lab Then Dose Them With Psychedelic Drugs

A brain of a deceased man in a jar Topical Press Agency/Getty

Psychedelic drugs have taken a new place in the popular imagination. Ayelet Waldman's book A Really Good Day details her experience with microdosing—taking small daily doses of LSD—to help her out of an intractable depression. She maintains it helped. In Silicon Valley, microdosing with psilocybin, the active compound in 'magic' mushrooms, has been hyped as a new fad. And a controversial documentary this past spring followed a young American man who traveled to Peru to cure his severe depression with ayahuasca, a psychedelic substance used in indigenous medicine.

It makes sense science would catch on. In a new study from Scientific Reports, using lab-grown mini-brains known as cerebral organoids, a group of researchers from Brazil set out to explain ayahuasca's effects on the human brain.

The idea was to find evidence for ayahuasca's potential as an antidepressant.

This is not, according to outside researchers, what happened.

The Brazilian team grew a batch of cerebral organoids for 45 days before splitting them into groups. One group was bathed in a compound isolated from ayahuasca, one group in alcohol, and one in normal medium. In hopes of understanding the drug's effects, they then looked to see which proteins were expressed in greater or lesser number. In the brains submerged in the ayahuasca substance, they found more proteins associated with a process that lays the groundwork for memory, as well as evidence of an anti-inflammatory effect which they took to be anti-depressant.

But every technology has its limits. And that, according to Michal Stachowiak, a researcher at the University of Buffalo, and Byoung-Il Bae of Yale, is where this study fell short.

"When we culture human organoids we get them to the size of 5 or 6 millimeters, we don't get them any further," Stachowiak told Newsweek. If grown any larger, the mini-brains would need nutrients and oxygen that human brains receive from blood.

At this size, these brains correspond to a 3- or 4-month-old embryo. That makes things tricky if you're using them to model the brains of full-grown adults.

"It's an interesting study" Stachowiak said, but "I'm not sure the model was properly developed. I'm skeptical this model could or should be used to reflect a full adult human brain." And that's key because drugs like ayahuasca enact their effects on networks of neurons, which don't exist in this kind of brain.

Still, the possibilities for this method, just five or six years old according to Stachowiak, are promising. Because cerebral organoids model the brain in the early stages of development, they can provide a much clearer picture of what goes on in the developing brain, a picture that scientists have tried to approximate by using animal models and donated brains of already deceased fetuses. They may also prove useful in studying diseases that affect the developing brain, for example, schizophrenia, Zika, and autism.

For studying the effects of drugs that do their thing on fully developed brains, Stachowiak says, organoids aren't the way, at least not now. But just as sure as the much longer, embattled conversation on psychedelics, their legalization, and their potential to help people continues, the science—of which there is no small amount—will as well.