Learning and memory — abilities associated with a brain or, at the very least, neuronal activity — have been observed in protoplasmic slime, a unicellular organism with multiple nuclei.
When the amoeba Physarum polycephalum is subjected to a series of shocks at regular intervals, it learns the pattern and changes its behaviour in anticipation of the next one to come1, according to a team of researchers in Japan. Remarkably, this memory stays in the slime mould for hours, even when the shocks themselves stop. A single renewed shock after a ‘silent’ period will leave the mould expecting another to follow in the rhythm it learned previously. Toshiyuki Nakagaki of Hokkaido University in Sapporo and his colleagues say that their findings “hint at the cellular origins of primitive intelligence”.
Slime moulds demonstrate primitive learning and memory.EYE OF SCIENCE/SPL