Cartilage in the brain morphs while we sleep, study shows

Cartilage in the brain morphs while we sleep – possibly explaining why a good snooze can help consolidate memories, a new study suggests. The neurons in our brains that exchange information and help us learn have a cartilage-like sheath around them, known as a perineuronal net (PNN). US researchers believe that sleeping loosens this net enough to make our strong memories stronger and our weak memories weaker, causing them to drop out. Using mice and brains from human donors, they worked out PNNs densities in brain regions involved in emotional memory processing during a day's body cycle. They found that PNNs change in their elasticity in a circadian manner – recurring naturally on a 24-hour cycle – but sleep deprivation can disrupt this cycle.