Neuroscientists unravel the mystery of the "Proust phenomenon"

Mouse olfactory bulb section. Epifluorescence microscopy image. © Jules Dejou, Claude Bernard University Lyon 1, 2026.

A team from the Lyon Neuroscience Research Centre (CNRS/Inserm/Claude Bernard Lyon 1 University) has identified the brain mechanisms underlying the "Proust phenomenon", whereby a familiar scent can trigger particularly vivid and emotionally charged childhood memories. Published in PLOS Biology, the study shows that olfactory experiences during early life leave a lasting imprint in the olfactory bulb, enabling childhood odours to reactivate memory and reward circuits later in life. As the brain matures, these memories become increasingly anchored in the neural networks involved in emotional processing.

The researchers also found that this form of olfactory memory develops through the repeated association of a scent with positive experiences during childhood. The study combined data collected from human volunteers with an experimental mouse model to investigate the biological basis of this phenomenon.

Source: Dejou J. et al. Positive early-life olfactory memory is rooted in the olfactory bulb and triggers large-scale changes beyond the olfactory system, PLOS Biology, 14 July 2026. DOI: 10.1371/journal.pbio.3003845.