Organoids give signals

A group of scientists from the University of California managed to create a pea-sized brain from human pluripotent stem cells. The mechanism of creation was as follows: placed in a culture fluid that mimics the environment of brain development, stem cells differentiated into different types of brain cells and self-organized into a three-dimensional structure resembling the human brain.

Scientists have grown hundreds of organoids for 10 months and monitored their electrical activity. It began to show up about two months later. The signals were rare and had the same frequency as in a very immature human brain. As the organoids continued to grow, they produced waves at different frequencies, and signals began to appear more frequently, which meant the development of neural networks.

To compare organoids with the human brain, scientists trained a machine learning model to recognize signs of brain activity using electroencephalograms of 39 premature infants aged 6 to 9.5 months. The algorithm predicted how many weeks the organoids developed in culture, which suggests that these organoids and the human brain have a similar growth and development trajectory. However, there is no evidence that they have higher nervous activity and have consciousness. They are still a rudimentary model: the rest of the brain structures are missing. Thus, the observed brain waves may have nothing to do with the activity of the real brain.

Up to this point, scientists have successfully grown organoids with cellular structures similar to those of the human brain, but none of the previous models had functional neural connections. The connections necessary for most types of brain activity appear and become interconnected at the time of neuronal maturation. American neuroscientists have managed to create the best mechanism for growing stem cells to date, largely due to the correction of the formula of the culture medium. The adjustments made allowed the organoids to become more mature than previous models.

In the future, scientists would like to improve organoids in order to be able to use them both for understanding the development of the nervous system, modeling various diseases, screening drugs, and for training artificial intelligence.

The article Trujillo et. al Complex Oscillatory Waves Emerging from Cortical Organoids Model Early Human Brain Network Development is published in the journal Cell Stem Cell.

Elena Panasyuk, portal "Eternal youth" http://vechnayamolodost.ru .