Nostalgia is a complex emotion that involves remembering events experienced in the past and it is mostly positive, but it is also mixed with some negative emotions. It involves a cognitive process called autobiographical memory; therefore, we first referred to neuroimaging studies of autobiographical memory. Autobiographical memory involves a network consisting of the hippocampus, temporal lobe, posterior cingulate cortex, prefrontal cortex, and cerebellum. We then introduced the few neuroimaging studies on nostalgia that have been reported to date. Most previous studies have focused on the positive aspects of nostalgia. As a result, brain regions associated with the reward system such as the midbrain and striatum and brain regions associated with autobiographical memory have been reported as nostalgia-related brain regions. As a future issue, investigators need to keep in mind that nostalgia has negative aspects such as a sense of loss and regret and to focus on individual differences in the ratio of positive to negative memories.
