From smell and sound to the Self : A systematic review on neural correlates and the emotional intensity of nostalgic memory retrieval

Sammanfattning

Nostalgia has transitioned from being viewed as a pathological condition to a recognized positive psychological resource that fosters self-continuity and social connectedness. While both music and scent are potent triggers for nostalgia, the neurocognitive differences between these sensory modalities remain under-explored. This systematic review compares the neural correlates and emotional intensity of music-evoked versus scent-evoked nostalgia, investigating the mechanisms underlying their adaptive functions. Based on a synthesis of six neuroimaging studies, the findings reveal that both modalities activate core regions of the Default Mode Network (medial prefrontal cortex, posterior cingulate cortex) and reward systems (medial orbitofrontal cortex, striatum). Yet, distinct sensory pathways emerge; scent-evoked nostalgia relies on a direct limbic pathway, providing immediate affective grounding and vivid episodic retrieval (the Proust phenomenon). In contrast, music-evoked nostalgia engages in a more distributed network involving higher-order cognitive processing and neural oscillations (theta, alpha, and gamma bands), facilitating sustained emotional integration and regulation. This suggests that sensory triggers serve complementary roles: scent acts as a rapid emotional anchor, while music supports a prolonged, integrative nostalgic state. These distinct neural pathways help explain how nostalgia may function as a flexible homeostatic resource for psychological resilience.