Sleep consolidates memories for competing tasks, researchers show

A good night's sleep helps the brain preserve memories of two competing tasks learned during the previous day, scientists found in a study using starlings as the animal model. Credit: Daniel D. Baleckaitis

Sleep plays an important role in the brain's ability to consolidate learning when two new potentially competing tasks are learned in the same day, research at the University of Chicago demonstrates.

Other studies have shown that sleep consolidates learning for a new task. The new study, which measured starlings' ability to recognize new songs, shows that learning a second task can undermine the performance of a previously learned task. But this study is the first to show that a good night's sleep helps the brain retain both .

Starlings provide an excellent model for studying memory because of fundamental biological similarities between avian and mammalian brains, scholars wrote in the paper, "Sleep Consolidation of Interfering Auditory Memories in Starlings," published in the current online edition of Psychological Science.

"These observations demonstrate that sleep consolidation enhances retention of interfering experiences, facilitating daytime learning and the subsequent formation of stable memories," the authors wrote.

The paper was written by Timothy Brawn, a graduate researcher in at UChicago; Howard Nusbaum, professor of psychology; and Daniel Margoliash, professor of psychology, organismal and . Nusbaum is a leading expert on learning, and Margoliash is a pioneer in the research of and its development in .

For the study, the researchers conducted two experiments using 24 starlings each. They played two recorded songs from other starlings and tested the birds' ability to recognize and repeat the two songs. After learning to recognize the two songs, the birds were later trained to recognize and perform a different pair of songs.

In their experiments, the authors examined the effect of sleep on the consolidation of starlings' memories. After learning the second pair of songs, they were tested on the first before they went to sleep. They varied the time between testing.

Researchers found that learning the second pair of songs interfered with the birds' ability to remember the first pair, regardless of the time between the daytime testing periods. Learning the first pair of songs also interfered with the birds' ability to remember the second pair when they were tested on the second pair before they went to sleep.

When the were allowed to sleep, however, they showed increases in performance on both the first and second pair of songs, suggesting that sleep consolidation enhances their memory, overcoming the effects of interference. When taught a new song pair after awaking, the birds were still able to remember what they had learned on the previous day, despite the new interference.

"The study demonstrates that sleep restores performance and makes learning robust against interference encountered after sleep. This process is critical to the formation and stability of long-term memories," Nusbaum said.

Related Stories

As in humans, sleep solidifies a bird's memories

Jan 12, 2010

Sleeping is known to help humans stabilize information and tasks learned during the preceding day. Now, researchers have found that sleep has similar effects upon learning in starlings, a discovery that will open up future ...

Sleep disturbances hurt memory consolidation

Mar 28, 2012

Sleep disturbance negatively impacts the memory consolidation and enhancement that usually occurs with a good night's sleep, according to a study published Mar. 28 in the open access journal PLoS ONE.

People learn while they sleep, study suggests

Sep 27, 2011

People may be learning while they're sleeping – an unconscious form of memory that is still not well understood, according to a study by Michigan State University researchers.

Sleep enforces the temporal sequence in memory

Apr 18, 2007

We have usually quite strong memories of past events like an exciting holiday or a jolly birthday party. However it is not clear how the brain keeps track of the temporal sequence in such memories: did Paul spill a glass ...

Sleep makes your memories stronger

Nov 12, 2010

As humans, we spend about a third of our lives asleep. So there must be a point to it, right? Scientists have found that sleep helps consolidate memories, fixing them in the brain so we can retrieve them later. Now, new research ...

Recommended for you

Study examines blood markers, survival in patients with ALS

11 hours ago

The blood biomarkers serum albumin and creatinine appear to be associated with survival in patients with amyotrophic lateral sclerosis (ALS) and may help define prognosis in patients after they are diagnosed with the fatal ...

Scientists find new clues to brain's wiring

Jul 18, 2014

New research provides an intriguing glimpse into the processes that establish connections between nerve cells in the brain. These connections, or synapses, allow nerve cells to transmit and process information involved in ...

User comments

Adjust slider to filter visible comments by rank

Display comments: newest first

arq
not rated yet Mar 21, 2013

Sleep helps in memory, attention, alertness, clarity of thought.

'Get sleep...get sharp!'