Tired? Hungry? Put the books down, says U of T Mississauga research

For most of us, it's a familiar feeling - the mental fogginess that comes after a sleepless night or when we're hungry. New research into fruit flies is now providing clues as to why some people are more susceptible to cognitive difficulties when missing sleep or food.

Biology professor Marla B. Sokolowski from the University of Toronto Mississauga and colleagues at Washington University School of Medicine in St. Louis have found connections between flies with ‘rover' and ‘sitter' variants of the foraging gene and how the fly reacts to a lack of sleep or food.

In the study, reported online in the Proceedings of the National Academy of Sciences, the team found that sleep-deprived ‘rover' flies do not suffer memory problems or show sleep rebound (the need to catch up on sleep). However, ‘sitter' flies demonstrate both when deprived of rest.

"We would expect that a behavioural advantage such as sleep resilience as shown by the ‘rover' flies would become standard through a population," says Sokolowski. "But there is a tradeoff."

The tradeoff is vulnerability to starvation, she says. While the ‘rovers' had no mental problems after sleep deprivation, memory was compromised when faced with a lack of food. "Conversely, the ‘sitter' flies, which were vulnerable to memory problems after sleep deprivation, had none when deprived of food," says Sokolowski. "The gene variant provides resilience in some environments but is detrimental in others."

By changing levels of the foraging gene enzyme Protein Kinase G (PKG), the team also identified a small region of the fly's brain where this tradeoff occurs.

"Humans have this same gene and enzyme, and the study opens a gateway to learning more about sleep resilience in people," says Paul Shaw, a professor of anatomy and neurobiology at Washington University and the study's senior investigator. "Understanding how tradeoffs confer benefits or disadvantages in specific environments may tell us more about the evolutionary need for sleep."

This study was funded in part by the Natural Sciences and Engineering Research Council of Canada (NSERC). The lead author was Jeffery Donlea, also from Washington University.

MEDIA CONTACTS

Marla B. Sokolowski
Department of Biology, University of Toronto Mississauga
Department of Department of Ecology and Evolutionary Biology, University of Toronto St. George
marla.sokolowski@utoronto.ca

Nicolle Wahl

U of T Mississauga Communications

905-569-4656

nicolle.wahl@utoronto.ca