What the Tiny Cluster of Brain Cells in My Lab Are Telling Me
My feeling was nothing less than elation. Tal Sharf, one of my post-doctoral fellows, called me from my neurobiology lab at the University of California, Santa Barbara, with the news that a tiny blob of tissue resembling a brain was talking in the only way it could. It was producing indecipherable electrical squiggles on a computer screen.
I was in a planning meeting for a class designed to link neuroscience and the humanities. My colleagues, professors in the art and music departments, were puzzled and curious about the enthusiasm written on my face. Wanting to keep the discussion grounded in science, not science fiction, I began to explain.
Was there a fragment of consciousness in the tissue speck, a whisper from the genes of the donor?
The tissue blob was called a brain organoid. It began as a biopsy from the skin of a donor and was planted on a culture dish. Four critical genes encased in a dagger-like microscopic vehicle were driven into the skin cells to erase their memories of having been skin, and then reprogrammed as stem cells. Stem cells, the source of the diversity among cell types in the body, from liver cells to hair follicles, from lung cells to lacrimal cells, have the potential to become any cell type in the human body.
My postdocs and I gently prodded the cells to become brain cells by providing the necessary chemical growth. Once in this new dimension, the diverse cell types shape themselves into the layered organization that loosely resembles, in miniature, a developing human brain, filled with tentacular axons coursing among the branches and twigs of tree-like dendrites dotted with synapses.
