Researchers at the University of Tokyo have created a method for growing and connecting single neurons using geometric patterns to route the neurons more precisely, cell by cell.
The article, “Assembly and Connection of Micropatterned Single Neurons for Neuronal Network Formation,” appeared in Micromachines, a journal of molecular machinery.
Thus far researchers have created simple brain matter using “in vitro cultures,” a process that grows neurons haphazardly in a clump. The connections associated with these cultures are random, thereby making the brain tissue difficult to study.
“In vitro culture models are essential tools because they approximate relatively simple neuron networks and are experimentally controllable,” said study author Shotaro Yoshida. “These models have been instrumental to the field for decades. The problem is that they’re very difficult to control, since the neurons tend to make random connections with each other. If we can find methods to synthesize neuron networks in a more controlled fashion, it would likely spur major advances in our understanding of the brain.”
Yoshida and the team looked more closely at how neurons behave and found that they could be trained to connect using microscopic plates made of “synthetic neuron-adhesive material.” They look like little frying pans with extra handles and “when placed onto the microplate, a neuron’s cell body settles onto the circle, while the axon and dendrites – the branches that let neurons communicate with each other – grow lengthwise along the rectangles.”
The researchers then connected the neurons, testing if they would fire simultaneously as predicted.
“What was especially important in this system was to have control over how the neurons connected,” Yoshida said. “We designed the microplates to be movable, so that by pushing them around, we could physically move two neurons right next to each other. Once we placed them together, we could then test whether the neurons were able to transmit a signal.”
“This is, to the best of our knowledge, the first time a mobile microplate has been used to morphologically influence neurons and form functional connections,” said investigator Shoji Takeuchi. “We believe the technique will eventually allow us to design simple neuron network models with single-cell resolution. It’s an exciting prospect, as it opens many new avenues of research that aren’t possible with our current suite of experimental tools.”
Unfortunately, this is just the first step for this technology, especially considering the millions of neurons necessary to eat, breathe, and sleep (and use the internet). It is, however, a good start.