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 of wine before or after Mary left the party?

Previous findings from a research group headed by Jan Born at the University of Lübeck have confirmed the widely held view that long-term memories are formed particularly during sleep, and that this process relies on the brain replaying recently encoded experiences during the night. The same research group now provides evidence that sleep not only strengthens the content of a memory but also the particular order in which they were experienced, probably by a replay of the experiences in "forward" direction.

Students were asked to learn triplets of words presented one after the other. Afterwards they slept, whereas in a control condition no sleep was allowed. Later, recall was tested by presenting one word and asking which one came before and which one came after during learning. Sleep was found to enhance word recall, but only when the students were asked to reproduce the learned words in forward direction.

This finding shows that sleep associated consolidation of memories enforces the temporal structure of the memorized episode that otherwise might be blurred to a timeless puzzle of experiences.

Citation: Drosopoulos S, Windau E, Wagner U, Born J (2007) Sleep Enforces the Temporal Order in Memory. PLoS ONE 2(4): e376. doi:10.1371/journal.pone.0000376

Source: Public Library of Science

Explore further: Organovo has 3D-printed liver tissue for drug testing

add to favorites email to friend print save as pdf

Related Stories

Space agency says Philae completes primary mission

11 hours ago

The pioneering lander Philae completed its primary mission of exploring the comet's surface and returned plenty of data before depleted batteries forced it to go silent, the European Space Agency said Saturday.

Watson-powered app to answer wellness-related questions

14 hours ago

A clinical laboratory that offers genetic testing services globally has received an investment from the IBM Watson Group. The bioinformatics market, which includes genetics, is expected to grow to $12.86 ...

Obama pushes for world climate pact after China deal

14 hours ago

A Sino-US breakthrough on reducing carbon emissions proves a global deal on climate change is achievable, US President Barack Obama said Saturday, as campaigners hailed new momentum in long-stalled talks.

Recommended for you

Organovo has 3D-printed liver tissue for drug testing

53 minutes ago

(Medical Xpress)—The commercial release of 3D printed liver tissue was announced earlier this week. Organovo is the company behind the release. The product is intended for use for preclinical drug discovery ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.