AI Insight
Researchers modeled childhood olfactory memory in mice by exposing them to pleasant odors during early life in positive environments. They found that specialized neurons born during the neonatal period in the olfactory bulb are essential for encoding and retrieving these early memories, with memory recall activating reward system networks in the brain. As memories age, their persistence depends on re-exposure to the original odor and involves a shift from reliance on neonatal neurons to strengthened connections in limbic brain regions.
Why it matters
This research reveals the neural mechanisms underlying how childhood sensory experiences shape long-term memory and brain structure. Understanding these processes could inform approaches to memory disorders, early childhood development interventions, and explain why certain childhood memories have lasting emotional significance throughout life.
Understand the Science
by Jules Dejou, Anna Athanassi, Théo Brunel, Marc Thevenet, Anne Didier, Nathalie Mandairon
Olfactory childhood memories are particularly important for forming one’s identity. However, we don’t know how they exert their privileged influence and shape brain structure. To address this, we modeled childhood olfactory memory in mice based on a human survey indicating that our earliest olfactory memory arises from repeated positive experiences paired with a pleasant odorant. Accordingly, mice were exposed during childhood to an attractive odorant in a playful environment. In adulthood, memory recall relied on neonatal-born granule cells (GCs) in the olfactory bulb, as their optogenetic silencing impaired retrieval, and on increased functional connectivity in the reward system. With age, memory persistence depended on re-exposure to the childhood odorant and was associated with the disengagement of neonatal-born GCs, alongside with strengthened limbic functional connectivity. Together, these findings identify neonatal neurons as a key substrate for encoding childhood olfactory memory and reveal dynamic reorganization of brain networks supporting its long-term significance.