By Jessica Tobacman, Special to the Tribune
April 10, 2013
Sleep helps the brain to better remember new material and differentiate between two new pieces of information, a study by University of Chicago scientists has found.
Working with two separate groups of 24 starlings each in two separate experiments, U. of C. professors Howard Nusbaum and Daniel Margoliash found that the birds were able to better recall songs sung by other starlings after they had slept. The birds also were better able to differentiate between other birds' songs more effectively after eight hours of sleep, the researchers found.
Nusbaum and Margoliash studied starlings because there are key similarities in brain function between starlings and humans.
"The similar pattern of memory consolidation in starlings … and humans … across waking and sleeping retention, coupled with the similarities between mammalian and avian sleep, suggest investigations of avian sleep and memory as an attractive comparative approach to understanding human memory consolidation," they wrote in a paper about their research that was published online last month in the journal Psychological Science.
Nusbaum and Margoliash tested how well the birds could recognize and repeat first one pair of songs previously recorded and sung by other starlings and then a second pair of songs. The birds were tested on their memories of the first pair of songs after learning the second set, and they demonstrated better recall after they slept, the researchers found.
Sleep apparently helped the starlings consolidate "the memory of both tasks," Nusbaum said. "It made both of them available and accessible. It was quite remarkable."
"Sleep pulls later and earlier memories apart, so that you have both memories," he added.
Kimberly Fenn, assistant professor of psychology at Michigan State University, called the study "ambitious and cleverly designed."
"There are several important findings that contribute substantially to the literature," Fenn said. "This paper is important because it has shown for the first time that sleep can enhance memory performance of two separate tasks even after both tasks had been impaired by interference. Critically, this paper lends insight to current studies on humans."
"This work has important implications for memory models, functional theories of sleep and education," she added.
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