The human brain is a complex biological processor made up of a network of billions of neurons. Thus, discovering its inner workings remains a challenge for scientists, who often develop simplified models to uncover its mysteries.
Now researchers at the Institute of Industrial Science at the University of Tokyo have created a model that uses microscopic plates to grow and connect neurons, literally, cell by cell.
Typically, brain research involves growing a network of neurons through “in vitro cultures,” which function as a stripped-down version of the human brain that can be “manipulated” chemically or electrically.
But in vitro culture models suffer from the problem of uncontrolled growth, as neurons start to make random connections with each other. This tendency of neurons makes it difficult to observe brain tissue.
A closer look at the behavior of neurons helped them determine that brain cells could be cultured in a more organized way through geometric patterns. So they created a microscopic plate made of a “synthetic neuronal adhesion material” to guide the cells’ growth.
The circular plate has two protruding rectangles that look like balls on a tight string. When a neuron is placed on the plate, the cell body squeezes into the circle while the axon and dendrites (which facilitate communication between them) grow along the rectangles.
Since the tiles are mobile, they could be physically moved to make connections with other neurons in the desired way. The researchers then tested the network of connected neurons to see if they could transmit a signal, and it worked!
"We believe that this technique will eventually allow us to design simple models of neural networks at single-cell resolution," said Shoji Takeuchi, the lead researcher on this project. "It is an exciting prospect, as it opens up many new avenues of research that are not possible with the current experimental toolkit.".
