Sleep makes flying smart
If many fruit flies live in a small space or they have to solve complex tasks, they sleep more. Researchers at the Neurosciences Institute in San Diego observed that these breaks appear to be important for processing the experience and forming memories.
Indrani Ganguly-Fitzgerald and her colleagues raised flies singly or in groups of more than thirty individuals. In comparison, the insects that were more exposed to social interactions required more sleep during the day. The more flies lived together, the longer rest periods they took during the day. Their need for nighttime sleep, on the other hand, was unchanged.
This was not the case for flies, which due to genetic changes could not see or smell and thus could not interact socially. They were just as agile as their he althy counterparts and therefore physically no less exhausted. However, Ganguly-Fitzgerald suspects that they were less aware of their busy surroundings and therefore did not have to process as much information during sleep phases.
The scientists found that the neurotransmitter dopamine and various genes involved in the formation of long-term memory were partly responsible for the longer naps in the more socially stressed flies. And no learning without sleep: once the flies had completed training for a specific task, they then extended their sleep time. If the scientists disturbed them during such a rest period and kept them awake, the insects remembered what they had learned less than those who were able to sleep through the night.
A connection between sleep and memory formation is already known for mice and humans. However, the exact physiological function of sleep is still relatively unclear. This commonality between humans and flies that has now been uncovered makes it possible to gain new insights based on their much more manageable nervous system, which can also be genetically manipulated.
