Why Some Memories Are So Vivid ?
Studies say that emotional experiences may help cement memories into the brain, which might explain why some recollections are so vivid. Memories are saved on different levels, with some staying in the brain for only a few seconds, others retrievable with some effort, while others are almost permanent.
"Rehearsal" of information can help strengthen the connections between neurons, or brain cells. It is the pattern of connections between neurons that forms the physical basis of memories.
Proteins are required to make the connections - and thus memories stick, but scientists were unsure whether the brain actually aimed the proteins at each individual recollection.
If an animal was feeling intense emotions during a significant experience, memories that would ordinarily be dropped were cemented in with the central recollection.
SOURCE: Fitness and Health. The Brain Stories