How good are you at remembering something you learned two weeks earlier? What if during the intervening 14 days, your head was removed? One flatworm isn't bothered by this scenario. After growing back its entire head and brain, it picks off pretty much where it left off.
The planarian is a modest little flatworm, the kind of common microscope denizen you might find in a Gary Larson cartoon. What's remarkable about it is its ability to regenerate. The whole body can regrow, head to eyespots to tail, from even a tiny fragment of the original animal.
Tal Shomrat and Michael Levin at Tufts University built a computerized apparatus for training planarians. Back in the 1960s, an intriguing line of research had suggested that the worms might be able to retain memories after decapitation. But researchers had done their training and testing by hand, a cumbersome method that led to inconsistent ...
