MRI
scans from a study being presented today at SLEEP 2012 reveal how sleep
deprivation impairs the higher-order regions in the human brain where food
choices are made, possibly helping explain the link between sleep
loss and obesity that previous research has uncovered.
Twenty-three
healthy adults participated in two sessions using functional magnetic resonance
imaging (fMRI), one after a normal night’s sleep and a second after a night of
sleep deprivation. In both sessions, participants rated how much they wanted
various food items shown to them while they were inside the scanner.
“Our
goal was to see if specific regions of the brain associated with food
processing were disrupted by sleep deprivation,” said lead author Stephanie
Greer, a graduate student at the Sleep and Neuroimaging Laboratory at the
University of California, Berkeley.
Results
show that sleep deprivation significantly impaired brain activity in the
frontal lobe, a region critical for controlling behavior and making complex
choices, such as the selection of food to eat. The study suggests that sleep
loss may prevent the higher brain functions normally critical for making
appropriate food choices, rather than necessarily changing activity in deeper
brain structures that react to basic desire.
“We
did not find significant differences following sleep deprivation in brain areas
traditionally associated with basic reward reactivity,” Greer said. “Instead,
it seems to be about the regions higher up in the brain, specifically within
the frontal lobe, failing to integrate all the different signals that help us
normally make wise choices about what we should eat.”
She
added that this failure of the frontal lobe to optimally gather the information
needed to decide on the right types of foods to eat – such as how healthy
relative to how tasty an item may be – may represent one brain mechanism
explaining the link between sleep loss and obesity.
“These
results shed light on how the brain becomes impaired by sleep deprivation,
leading to improper food choices,” Greer said.
