The nostalgic brain: Its neural basis and positive emotional role in resilience

Abstract

People sometimes experience an emotional state known as ʼnostalgia’, which involves experiencing predominantly positive emotions while remembering autobiographical events. Nostalgia is thought to play an important role in psychological resilience. Here, we examined the brain activity and subjective feelings associated with nostalgic experiences, using childhood-related visual stimuli. We confirmed the presence of nostalgia-related activity in both memory and reward systems, including the hippocampus (HC), substantia nigra/ventral tegmental area (SN/VTA), and ventral striatum (VS). We also found significant HC-VS co-activation, with its strength correlating with individual nostalgia tendencies. Factor analyses showed that two dimensions underlie nostalgia: Emotional and personal significance and chronological remoteness, with the former correlating with caudal SN/VTA and left anterior HC activity, and the latter correlating with rostral SN/VTA activity. These findings demonstrate the cooperative activity of memory and reward systems, where each system has a specific role in the construction of the factors that underlie the experience of nostalgia. Based on these findings, we propose a “nostalgia-related network”, and discuss its functions during nostalgic experiences and its effects on human resilience. Furthermore, we discuss the possibility that nostalgia is one of the defensive mechanisms which we developed “towards independence” from a caregiver in childhood. That is, we have an exquisite brain mechanism by which our own memory can stimulate our own reward system in adversity, and recalled memories can be overwritten more positively after nostalgic experiences.