Ingfei Chen in Scientific American: (From 2012)
Amid the endless stream of everyday experience, emotion is like a blazing neon tag that alerts the brain, “Yoo-hoo, this is a moment worth remembering!” The salience of the humdrum sandwich you ate for lunch pales in comparison, consigning its memory to the dustbin. Yet emotions regulate our recall of not just our most riveting moments. Researchers now recognize that the same neural mechanisms involved in flashbulb memories underlie recollections along the continuum of human emotional experience. When people view a series of pictures or words in the laboratory, any emotionally laden content sticks in their head better than neutral information.
Memory is a three-stage process: First comes the learning or encoding of an experience; then, the storage or consolidation of that information over many hours, days and months; and last, the retrieval of that memory when you later relive it. Insights into how emotion modulates this process emerged from studies of conditioned fear responses in rats in the 1980s and 1990s by neuroscientists Joseph E. LeDoux, now at N.Y.U. [see “Mastery of Emotions,” by David Dobbs; Scientific American Mind, February/March 2006], and James L. McGaugh of the University of California, Irvine, among others. Their work established that the amygdala, a structure buried deep within the brain, orchestrates the memory-boosting effects of fear.
More here. (Note: Reading Proust these days has reignited my interest in memories. We know shockingly little about the science)