The quest for finding the root cause of autism and epilepsy has led to the complexities of brain development at the prenatal stage.
This was borne by the results on brain defects after studies by researchers who converted skin cells of patients into induced pluripotent stem cells and generated brain organoids. These 3D tissues bear a close resemblance to a human brain in the process of development.
The scientists from Stanford University grew forebrain circuits at one-sixteenth of an inch. Cortex is the outermost layer of the brain and the seat of all high-order mental functions.
Brain Building Vulnerable To Genetic Aberrations
However, cortex building process can also go awry due to genetic aberrations and can spark neuro developmental brain disorders including autism, schizophrenia, and other conditions.
During the trails, the Stanford researchers were able to watch the growth process of the brain when they grew brain cells in a petri dish.
They watched neurons migrating from one part of the brain to another region for making the cortex.
"We've never been able to recapitulate these human-brain developmental events in a dish before," said senior author Sergiu Pasca, assistant professor of psychiatry and behavioral sciences.
By seeing the process in real time for the first time and watching neurons coiling in the target areas, the formation of a web of active circuits at the cerebral cortex was vividly understood. The process normally happens in the second half of pregnancy.
The study was also an assertion that the neuroscientists can monitor and manipulate neural spheroids derived from pluripotent stem cells.
The important conclusion was that skewed brain cell cluster migration is induced by autism-related disorders. Also, the role of Timothy syndrome in activating autism, epilepsy, and heart disease was highlighted. The defects and delays in neuronal migration were also accounted for.
What Are Minibrains?
The research requires a clear understanding of the concept of minibrains vs. actual brains. Minibrains are clusters of organoids or spheroids created from skin cells and converted into neural stem cells. They can grow into structures like the brain circuits and galvanize networks of communicative cells.
Pasca explains the production of neural spheroids from Induced Pluripotent Stem Cells (iPS cells) and how they put them in culture dishes where the bottoms are coated to thwart neuron coiling.
These cells float in broth rich in nutrients and round balls where an average 1 million cells are housed. The spheroids are also the replica of human cerebral cortex and neurons. The neuron type was similar to those seen in cerebral cortex called as glutamatergic neurons.
The findings of the study hold the potential for customized study on psychiatric disorders in different individuals.
Insights On Many Neurological Disorders
Scientists are upbeat that these lab creations can unravel neurological diseases such as schizophrenia, autism, and Alzheimer's and are better off than traditional trials done on mouse brains.
The study's core conclusion is that genetic mutation associated with autism and epilepsy are linked to reasons that impede proper migration of brain cells from one cluster to another.
"They were sort of left behind," commented Pasca.
The study has been published in the journal Nature.
Though brain organoids will not grow big or perform like a complete brain, they are valuable as a window to study brain's development during pregnancy.