Do flies have memories?
Yes. A fruit fly can learn that a smell means food or danger and remember it for hours or days. The memory forms in the mushroom body.
In experiments, flies that meet a smell together with sugar later walk toward that smell, and flies that meet it with a mild electric shock avoid it. They have learned, and they can remember it for hours, sometimes for days.
The learning happens in the mushroom body. About 2,000 Kenyon cells on each side of the brain give every smell its own pattern, and output neurons read that pattern. When a smell comes with a reward or a punishment, the synapses between the two groups change strength. Scientists think that change is the memory. The WiredMind lesson shows this pathway, but nothing in it learns: its connections never change.
See it in a lesson
Key terms
- Mushroom body
- A mushroom-shaped part of an insect’s brain where smells are sorted and smell memories are stored.
- Kenyon cells
- The small nerve cells of the mushroom body. Each smell switches on a different handful of them, so every smell gets its own pattern.
- Output neurons
- Nerve cells that read the pattern of the Kenyon cells and pass it on to the rest of the brain. Scientists call them MBONs, short for mushroom body output neurons.
- Synapse
- The junction where one neuron passes its signal to the next. The more synapses two cells share, the stronger the link between them.