The best mimic of a human brain we have to date isn’t a program running on a sophisticated supercomputer, but a blob of silk and collagen gel that more closely resembles a preschooler’s art project than a state-of-the-art neuroscience research program.
The blob, which contains live neurons that signal one another across the membrane’s center, is evidence that a brain-like substance can exist and survive outside of the body, and for quite some time. It’s also the first time scientists have been able to closely imitate mechanics of the brain in the laboratory. David Kaplan, a bioengineer at Tufts University, and his colleagues published their results Monday in the Proceedings of the National Academy of Science.
While the current model only uses rat neurons, adding human neurons to the mix could help scientists better understand various neurobiological functions. It could also aid important research on the effect of disease, trauma, and drugs on the brain.
Here’s Pam Belluck, writing for The New York Times:
Dr. Kaplan’s team found that a spongy silk material coated with a positively charged polymer could culture rat neurons, a stand-in for gray matter. By itself, silk did not encourage neurons to produce axons, branches that transmit electrical pulses to other neurons.
The researchers formed the silk material into a doughnut and added collagen gel to the center. Axons grew from the ring through the gel — the white matter substitute — and sent signals to neurons across the circle.
Kaplan’s team was able to sustain activity in the doughnut for two months—an impressively long time—by providing the cells with nutrients and growth factors. They also showed that the smart blob could react like a simple brain would. It’s neurons died after being exposed to neurotoxins, and when researchers dropped weights on it, levels of levels of the neurotransmitter glutamate spiked, just as you’d expect after a traumatic injury.
Despite the mimic’s apparent simplicity, scientists not involved in the study were quite impressed with the level of brain function it could emulate. One even went so far as to tell Belluck, “It’s best model I’ve seen.”