Researchers believe they've discovered 'anti-memories'

Memories, at their fundamental level, are simply electrical connections between neurons. When you make a new memory, the connection between a set of neurons is strengthened. However, if that were the only mechanism in play, the development of new memories would eventually lead to runaway electrical activity in the brain. There must be, as the Oxford team hypothesizes, an inhibiting system that keeps that activity in check. And that's where anti-memories come in.