Well-rested flies briefly shed learning troubles

The study results reinforce the therapeutic benefits of sleep, even if the different functions of sleep remain mysterious, says Leonie Kirszenblat. (Credit: elizabeth lies/Unsplash)

New research with flies suggests that a good night’s sleep might be vital for retaining our capacity to learn and remember.

Leonie Kirszenblat, a PhD student at University of Queensland, says the research shows increased sleep temporarily treated flies with learning defects, leading to a 20 percent improvement on a memory task.

The researchers used different genetic or pharmacological methods to induce the flies’ sleep, to prove that it was indeed sleep that treated the flies, rather than any specific drug or genetic pathway.

“One way we test and measure the flies’ memory is to use a visual learning task in which they must learn to avoid light that they are normally drawn to, by associating it with punishment,” says Associate Professor Bruno van Swinderen of the university’s Queensland Brain Institute.

“We test and measure their sleep by probing their responsiveness to different vibration intensities throughout successive days and nights, using a sophisticated computer interface we call DART: Drosophila ARousal Tracking.”

Mysterious sleep

The study results reinforce the therapeutic benefits of sleep, even if the different functions of sleep remain mysterious, says Kirszenblat.

“A lot of human disorders result in sleep problems. For instance, many Alzheimer’s disease patients report problems sleeping,” she says. “But in humans, it is difficult to determine causality: does bad sleep lead to cognitive disorders, or do these disorders cause bad sleep?”

The study used strains of flies with severe learning defects, or flies with memory problems that develop as they age.

“We forced them all to sleep for two days, and afterwards they all became normal learners,” says Kirszenblat.

“For example, we tested flies with a mutation in a gene called presenilin, which has been linked to early-onset Alzheimer’s disease, and we put the flies to sleep by activating GABA-A receptors in their brain—which humans also have.

“So it’s possible that simply by finding effective methods of promoting natural sleep, perhaps we will see some improvement in patients’ conditions.”

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Humans and flies share most genes that are important for memory, leading the researchers to conclude that the work could lead to discoveries about improving memory in humans.

“The next step is to understand the actual mechanism that improves memory after sleep,” says Kirszenblat. “If we could understand how sleep improves memory in the fly brain, perhaps these mechanisms could be tweaked to improve memory in humans as well.”

The research, led by Washington University, appears in Current Biology.

Source: University of Queensland