Researchers have found that birds, like humans, stabilize information and tasks learned during the preceding day during sleep.
"We really wanted to behaviorally show that these types of sleep-dependent memory benefits are occurring in animals," said lead author Timothy Brawn, graduate student at the University of Chicago. "What was remarkable was that the pattern here looks very similar to what we see in humans. There wasn’t anything that was terribly different."
To conduct the study, Brawn and colleagues trained starlings to discriminate between two 5-second snippets of birdsong in a learning task called a go-nogo procedure. If the starlings heard one song, the "go" stimulus, they would receive a food pellet after correctly poking their beak into a hole in their cage. If the other song, the "no-go" stimulus, was played, it signaled that the bird should not poke its beak in the hole, or else the lights in the cage were briefly shut off.
Groups of starlings were trained in the task at different times of day, then retested later to see how well they retained their learning. In all groups, performance on the task improved after the birds slept, relative to their performance before sleep. This result replicated the sleep-dependent enhancement pattern observed in human studies.
"In human studies, we can’t control what they’re doing throughout the day," Brawn said. "In starling experiments, they don’t have any other interactions. … I think there’s a much reduced interference effect here."
According to Brawn, now future experiments with starlings and humans can directly study the effects of interference on learning and how sleep may overcome those effects.
"The result suggests this is a very broad, general phenomenon that might be shared across a great many vertebrates," said researcher Daniel Margoliash, PhD, professor of organismal biology, psychology and neuroscience. "It was quite important to show that and it now opens the possibility for mechanistic and behavioral experiments in animals that are difficult to do in humans."
The research appears in the Journal of Neuroscience.
Getting Smarter While You Sleep