Nostalgia is a complex emotion that is thought to be processed by various areas of the brain, including the hippocampus, amygdala, and ventromedial prefrontal cortex. The hippocampus is involved in memory formation and retrieval, and is thought to play a role in the ability to recall past experiences. The amygdala is involved in processing emotions, and may contribute to the emotional aspects of nostalgia. The ventromedial prefrontal cortex is involved in the evaluation of emotions and may play a role in the subjective sense of nostalgia.