Sleep is an essential component of the anti-aging lifestyle, as it enables the body’s cells, tissues, and organs to perform restorative functions.  Matthew Walker, from the University of California/Berkeley (California, USA), and colleagues have found that while we sleep, bursts of brain waves known as "sleep spindles" promote networking between key regions of the brain involved with learning. These electrical impulses help to shift fact-based memories from the brain's hippocampus – which has limited storage space – to the prefrontal cortex's "hard drive," thus freeing up the hippocampus to take in fresh data. Spindles are fast pulses of electricity generated during non-REM sleep, and they can occur up to 1,000 times a night.   The team found that spindle-driven networking was most likely to happen during Stage 2 of non-Rapid Eye Movement (NREM) sleep, which occurs before we reach the deepest NREM sleep and the dream state known as Rapid Eye Movement (REM) sleep.  The researchers conclude that: “We report here a learning interaction, such that …  sleep and associated NREM spindle oscillations restore efficient learning ability.”