Representational image of a neuron system. Getty
Johns Hopkins University researchers have developed a novel whole-brain organoid.
This model is unique because it features connected neural tissues from various brain regions and even includes basic blood vessels.
The newly developed organoid is smaller than a real brain, containing “6 to 7 million neurons” compared to the tens of billions found in adult brains.
Despite its size, it offers a unique platform for studying whole-brain development.
It could advance the study of neuropsychiatric disorders like autism and schizophrenia.
“Most brain organoids that you see in papers are one brain region, like the cortex or the hindbrain or midbrain. We’ve grown a rudimentary whole-brain organoid; we call it the multi-region brain organoid (MRBO),” added Annie Kathuria, an assistant professor in JHU’s Department of Biomedical Engineering.
Annie Kathuria and team Credit: Will Kirk / Johns Hopkins University
Brain organoid development is a unique and incredibly promising frontier in biomedical science. These complex, lab-grown cultures are mostly crafted from pluripotent human stem cells.
Dr. Kathuria and her team first grew neural cells from different brain regions and early forms of blood vessels in separate dishes.
After growing the separate components, researchers fused them using special sticky proteins. This enabled the tissues to connect, grow together, and then begin producing electrical activity, functioning as a cohesive network.
The multi-region mini brain organoid successfully maintained a wide variety of neuronal cell types—showcasing the characteristics of a 40-day-old human fetal brain.
Notably, about 80% of the cell types typically found in early human brain development were equally present in these lab-grown miniaturized brains.
The researchers also observed the early formation of a blood-brain barrier, a protective layer of cells that regulates what enters the brain.
But why is this so significant?
“We need to study models with human cells if you want to understand neurodevelopmental disorders or neuropsychiatric disorders, but I can’t ask a person to let me take a peek at their brain just to study autism,” Kathuria said.
“Whole-brain organoids let us watch disorders develop in real time, see if treatments work, and even tailor therapies to individual patients,” the lead author added.
This advance opens up possibilities for studying complex neurological diseases that affect the entire brain — work previously confined to animal models.
It could also revolutionize drug development.
A major challenge in drug development is the high failure rate in early clinical trials: 85% to 90% of all drugs fail.
For neuropsychiatric drugs, that number jumps to 96%. This is primarily because current research depends on animal models, which often fail to mimic human biology accurately.
More accurately reflecting the natural development of a human brain, whole-brain organoids are likely to prove superior as test subjects.
“Diseases such as schizophrenia, autism, and Alzheimer’s affect the whole brain, not just one part of the brain. If you can understand what goes wrong early in development, we may be able to find new targets for drug screening,” Kathuria said.
“We can test new drugs or treatments on the organoids and determine whether they’re actually having an impact on the organoids.”
Though not sentient, these lab-grown organoids can sometimes serve as “basic minds” to perform simple cognitive tasks such as memory and learning.
While earlier versions were limited to two dimensions, newer three-dimensional organoids can even play simple games like Pong.
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