Brain Waves Detected in Mini-Brains Grown in a Dishhttps://phys.org/news/2019-08-brain-mini-brains-grown-dish.htmlMachine Learning Algorithm Can't Distinguish Lab Mini-Brains from Preemie Babieshttps://medicalxpress.com/news/2019-08-machine-algorithm-distinguish-lab-mini-brains.htmlScientists have created miniature brains from stem cells that developed functional neural networks. Despite being a million times smaller than human brains, these lab-grown brains are the first observed to produce brain waves that resemble those of preterm babies. The study, published August 29 in the journal
Cell Stem Cell, could help scientists better understand human brain development.
The electrical impulse pattern for nine-month-old brain organoids revealed similar features to those of a premature infant who had reached full-term (40 weeks gestation).
In the latest study, Muotri and colleagues optimized every step of brain organoid construction. For example, they started from single cells, rather than the clumps of cells used in most protocols. They also tweaked the precise timing and concentration of factors added to prompt brain cell organization. There wasn't a single secret ingredient or innovation, he said, but rather several improvements over time.
The optimization paid off in terms of cellular diversity and cellular network activity. For example, the team detected a particular primate-specific neuron, called a cortical GABAergic neuron, that had never before been generated in a lab dish. According to Muotri, these cells are important players in the sophistication of neural networks.
To measure cellular network activity, the researchers grew their newly optimized brain organoids on multi-electrode arrays. The electrodes capture and record electrical impulses, which appear as patterns of waves and spikes in an EEG read-out. With the new protocol, the brain organoids went from producing 3,000 spikes per minute to 300,000 spikes per minute.
To compare the brain wave patterns of organoids with those of human brains early in development, the team trained a machine learning algorithm with brain waves recorded from 39 premature babies between six and nine-and-a-half months old. The algorithm was able to predict how many weeks the organoids have developed in culture, which suggests these organoids and human brain share a similar growth trajectory.
Open Access: Trujillo, Gao, and Negraes et al.:
"Complex oscillatory waves emerging from cortical organoids model early human brain network development",
Cell Stem Cell