'We can't answer these questions': Neuroscientist Kenneth Kosik on whether lab-grown brains will achieve consciousness

Brain organoids are 3D, lab-grown models designed to mimic the human brain. Scientists normally grow them from stem cells, coaxing them into forming a brain-like structure. In the past decade, they have become increasingly sophisticated and can now replicate multiple types of brain cells, which can communicate with one another.

This has led some scientists to question whether brain organoids could ever achieve consciousness. Kenneth Kosik, a neuroscientist at the University of California, Santa Barbara, recently explored that possibility in a perspective article. Live Science spoke with Kosik about how brain organoids are made, how similar they are to human brains and why he believes that brain organoid consciousness is not likely anytime soon.

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EC: What are brain organoids, and how do scientists make them?

Kenneth Kosik: A brain organoid is made from stem cells. You can take any person and convert their, say, skin fibroblasts into stem cells, and then differentiate them into neurons. It's what stem cells are all about — stem cells are called "pluripotent" because they can make any cell in the body.

We spent a fair amount of time before organoid technology came along, taking human-induced pluripotent stem cells and inducing them in a two-dimensional array to look at neuronal differentiation.

So that takes us halfway there. But it only gets us as far as two dimensions. And then the big insight, which came from Yoshiki Sasai in Japan and Madeline Lancaster, was to take these neurons that were beginning to differentiate — cells relatively early in development — and put them in a drop of what's called Matrigel — a gel that can be either a liquid or a solid depending on the temperature.