Diana Gabaldon said this quote

It was one of those strange moments that came to him rarely, but never left. A moment that stamped itself on heart and brain, instantly recallable in every detail, for all of his life. There was no telling what made these moments different from any other, though he knew them when they came. He had seen sights more gruesome and more beautiful by far, and been left with no more than a fleeting muddle of their memory. But these-- the still moments, as he called them to himself-- they came with no warning, to print a random image of the most common things inside his brain, indelible.