By 3 News online staff
The first nearly complete brain has been grown in a laboratory, exciting scientists because it could allow more ethical and rapid testing of experimental drugs and is an alternative to using rats.
Scientists at Ohio State University say the brain, which is the about the size of a pencil eraser, has the maturity of a five-week-old foetus and has 99 percent of the genes present in the human foetal brain.
The brain organoid was engineered from adult human skin cells.
Professor of biological chemistry and pharmacology at Ohio State University Rene Anand says it's the most complete human brain model developed so far.
"It not only looks like the developing brain, its diverse cell types express nearly all genes like a brain.
"We’ve struggled for a long time trying to solve complex brain disease problems that cause tremendous pain and suffering."
He says it gives scientists "better and more relevant" options to develop therapeutics than using lab rats.
Disappointing results using rodents for an experimental autism drug led Prof Anand to start his work on growing the human brain.
Using fewer animals will improve research because they're not as likely to predict what would happen in a human brain.
The brain is missing the vascular system, made up of vessels which carry blood through the body, but does have a spinal cord, all major regions of the brain, multiple cell types and a retina.
Prof Anand believes it has the potential to increase the pace of neuroscience research.
It takes about 15 weeks to build a model system developed to match the lab-grown brain.
Prof Anand and his colleague Susan McKay, a research associate in biological chemistry and pharmacology, have let the analogue brain grow to the 12-week point, with expected maturation changes seen along the way.
"If we let it go to 16 or 20 weeks, that might complete it, filling in that 1 percent of missing genes. We don't know yet," he says.
It has already been used to create brains with Alzheimer's and Parkinson's diseases as well as autism.