Our brain works day and night
It's a well-known fact that when we learn something new, our brains replay this information when we sleep to be sure to remember it later. But according to PLoS Biology, using functional Magnetic Resonance Imaging (fMRI), Belgian researchers have now demonstrated that asleep or awake we retain memory. Even during the day, when we are engaged into other activities, our brain reprocesses the information acquired a few minutes ago.
Here is how PLoS Biology introduces this advance.
Taking advantage of the new opportunities offered by 3 Tesla's functional Magnetic Resonance Imaging (fMRI), Philippe Peigneux [and his colleagues at the University of Liège] recorded (or scanned) the cerebral activity of volunteers while they performed a ten-minute auditory attention task every half hour in two sessions spaced out over a few weeks.
Here is a diagram showing the conditions of the experiment (Credit: PLoS Biology).
All participants underwent four fMRI scanning sessions (I–IV) within a half-day. In scanning session (I), they performed an auditory oddball task during which they mentally counted the number of deviant tones interspersed in a flow of repeated tones. Participants were then trained during 30 min outside of the scanner (training), either to the spatial memory navigation task (red path), or to the procedural memory SRT task (blue path). Immediately after the end of the training session, they were scanned again (II) while performing the auditory oddball task. They were then allowed a further 30-min break outside of the scanner without any further practice (rest). They were scanned once again (III) while performing the auditory oddball task. Afterwards, participants' memory of the learned task was tested outside of the scanner (retest). Finally, participants underwent a fourth fMRI session (IV), during which they explored virtual environments (red path) or practiced motor sequences in the SRT task (blue path), to determine the set of brain areas associated with task practice.
And here is an illustration showing "the task-specific modulation of regional brain responses by prior learning" (Credit: PLoS Biology). You'll find more details about this process here
What can we conclude from this research?
This study from the ULg Cyclotron Research Centre demonstrates for the first time that the human brain does not simply put newly acquired information in standby until there is a period of calm or sleep to strengthen them. Rather, the brain continues to process them dynamically as soon as the learning episode has ended, even if it has to face an uninterrupted series of completely different cognitive activities.
For more information, this research work has been published by PLoS Biology under the name "Offline Persistence of Memory-Related Cerebral Activity during Active Wakefulness" (Volume 4, Issue 4, April 2006). Here is a link to the full paper.
Sources: PLoS Biology, via EurekAlert!, March 27, 2006; and PLoS Biology web site
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