Whatever you happen to call them — crawfish, crawdads, mudbug — crayfish are pretty tasty. They also have a pretty remarkable ability to regenerate neurons from blood cells. Understanding brain regeneration in these little crustaceans might one day help us understand how it could work in humans.
This discovery that a creature that can continually make new neurons is startling and exciting. In our human brains, new neurons will sometimes grow but only from stem cells. And we can sometimes even turn mature cells into stem cells through a very specific and artificial process in a lab. In crayfish, however, the whole process seems to happen naturally.
To replenish neurons in damaged eye stalks and olfactory circuits, crayfish simply take cells from their blood and turn them into neurons. New Scientist explains:
To do so, they utilise what amounts to a "nursery" for baby neurons, a little clump at the base of the brain called the niche.
In crayfish, blood cells are attracted to the niche. On any given day, there are a hundred or so cells in this area. Each cell will split into two daughter cells, precursors to full neurons, both of which migrate out of the niche. Those that are destined to be part of the olfactory system head to two clumps of nerves in the brain called clusters 9 and 10. It's there that the final stage of producing new smell neurons is completed.
The catch is that crayfish are not exactly humans, which is quite obvious when you stare down at a dinner plate full of them. As invertebrates, they don't technically have "blood" but a fluid called haemolymph that circulates in their body. These cells in the haemolymph that turn into neurons, which called haemocytes, are very different from our red blood cells or haematocytes, despite the similar spellings. Nevertheless, it's one of those cool discoveries that shows the value of research into obscure, little creatures. And maybe someday we'll be able to steal their super powers. [New Scientist]
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