A group of researchers from the University of Cambridge have grown a miniature (roughly pea-sized) brain in a dish which they claim might “improve our understanding of human brain development and neurological disorders”.
The paper accompanying the work, published in the journal Nature Neuroscience, details how a grey blob of human stem cells placed next to 1mm-long slices of spinal cord and muscle tissue from a mouse spontaneously grew tendril-like connections and fused with it.
Furthermore, using long-term live microscopy and electrode arrays to measure neural activity, the researchers managed to record the “mini-brain” sending electrical signals to the muscle cells, thereby contracting them, which has never been demonstrated before.
To grow the “mini-brain on the move” (in the words of lead author on the study Madeline Lancaster), the researchers deployed a novel method which allowed it to reach a more sophisticated level than ever before, approximating the 12-16 week human foetal brain in terms of neuronal diversity and organisation.
The new method in question consists of putting a half millimetre-thick slice of the organoid on a porous membrane and sending it floating on the surface of a nutrient-rich liquid, thereby solving the problem of insufficient nutrient and oxygen supply at the centre of the tissue once it reaches a certain size, which plagued researchers in the past.
Even though neural tissue of such complexity is highly unlikely to produce any conscious phenomena, it is still “a good idea” to at least consider the possibility every time a new-and-improved-technique rolls around, claimed the team, noting that we are, nonetheless, still “very far away from that [conscious artificial brains]”.
Despite their relatively low complexity and size, organoids of this type could still be useful in improving our understanding of neural development: “Obviously we’re not just trying to create something for the fun of it,” said Lancaster. “We want to use this to model diseases and to understand how these networks are set up in the first place”.