SAN DIEGO -- Miniature human brain models grown from stem cells make brain waves like those in prematurely born babies, according to a study from University of California San Diego scientists.
This activity has never been seen before in the mini-brains or "organoids," said Alysson R. Muotri, a UCSD stem cell researcher. Muotri led the study with Bradley Voytek, a UCSD associate professor of cognitive science.
The organoids are made with stem cell technology invented in 2008 and are getting steadily more complex. This raises the question of whether they can acquire consciousness -- or already have.
The organoids grow in diameter to about 2/10ths of an inch, or half a centimeter, Muotri said, and live for about two years. When they were about nine months old, the organoids began producing complex electrical signals comparable to that of a premature infant who had reached the normal span of a pregnancy.
The study was published in late August in the journal Cell Stem Cell. Go to http://j.mp/minibrainwaves to read it.
The brain organoids were grown from tissue samples, Muotri said. These cells were made to regress to a state resembling that of embryonic stem cells, then developed into brain tissue.
Muotri is using these brain organoids to study the origins of autism. Organoids generated from autistic individuals are being compared with those from "neurotypical" individuals to see if there's a difference in how the organoids develop, Muotri said.
Organoids made to resemble brains and other organs have become an important tool for modeling human biology in recent years. These can be studied to understand cellular function in a three-dimensional model, which shows details not revealed in two-dimensional cell cultures or animal studies.
Brain organoids provide the only model of how human brains develop from the start, Muotri said. It's not ethical to probe development of normal babies as they grow during pregnancy.