memories

As sufferers of post-traumatic stress syndrome know all too well, frightening experiences can be strong, long-lasting and notoriously difficult to erase. Now, we're starting to understand why. Far from trying to purge these memories, the brain actively protects them by hiring a group of molecular bodyguards called CSPGs (or chondroitin sulphate proteoglycans in full). By studying the brains of rats, Nadine Gogolla from Harvard University found that CSPGs - large chains of sugars and proteins - accumulate in the space around nerve cells and form defensive nets around a select few. Dissolve…