Biology subjects

Mandairon, N.

Publications and source records attributed to Mandairon, N..

6 recordsLinked to original sources

bioRxiv2026

The formation and content of odor memory from childhood

As illustrated by Marcel Prousts madeleine, childhood olfactory autobiographical memory carries a stronger positive emotional valence than memories associated with other senses. However, little is known about its content or the conditions of encoding and maintenance. Here, we asked 647 participants to freely recall and characterize their earliest childhood olfactory memory. We found that this memory is typically encoded around age six, involves pleasant odors embedded within rich multisensory contexts, and retains a strong positive emotional valence despite age-related declines in some experiential qualities. The most frequently reported scenes took place at home, in the presence of the mother, and were predominantly associated with food-related odors, although natural-vegetation odors were also commonly reported. By contrast, the non-olfactory memory is encoded earlier, visually dominated, less multisensory, less pleasant, and more frequently associated with institutional settings and friends. These findings characterize childhood olfactory memory and highlight its distinctive content among autobiographical memories.

neuroscience↗

bioRxiv2026

Engram and neural underpinning dynamics of the long-lasting childhood olfactory memory

Olfactory childhood memories are particularly important for forming ones identity. However, we dont 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 a pleasant odorant in a playful environment. In adulthood, memory recall relied on neonatal-born granule cells 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 granule cells, 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.

neuroscience↗

bioRxiv2024

Enhancing Statistical Power While Maintaining Small Sample Sizes in Behavioral Neuroscience Experiments Evaluating Success Rates

Studies with low statistical power reduce the probability of detecting true effects and often lead to overestimated effect sizes, undermining the reproducibility of scientific results. While several free statistical software tools are available for calculating statistical power, they often do not account for the specialized aspects of experimental designs in behavioral studies that evaluate success rates. To address this gap, we developed "SuccessRatePower" a free and user-friendly power calculator based on Monte Carlo simulations that takes into account the particular parameters of these experimental designs. Using "SuccessRatePower", we demonstrated that statistical power can be increased by modifying the experimental protocol in three ways: 1) reducing the probability of succeeding by chance (chance level), 2) increasing the number of trials used to calculate subject success rates, and, in some circumstance, 3) employing statistical analyses suited for discrete values. These adjustments enable even studies with small sample sizes to achieve high statistical power. Finally, we performed an associative behavioral task in mice, confirming the simulated statistical advantages of reducing chance levels and increasing the number of trials in such studies

neuroscience↗

bioRxiv2023

A pilot study of the impact of smells on the behavior of level 3 autistic children and adolescents during an ongoing task

The present pilot study aims to perform a first evaluation of the effect of smells on the behavior of autistic children and adolescents (level 3) while they are performing a routine task and are going through a more or less intense crisis situation. To do this, we developed a protocol adapted for a field study in the familiar environment (specialized school) of 8 autistic children and adolescents, where the effect of odors on the behaviors of screaming, agitation, and aggression was assessed. First, it was possible to carry out this protocol on this level 3 autistic population. Second, the results acquired on subjective data collected by the experimenter suggest that odors may reduce certain behavioral traits such as agitation or screaming. These data should be considered as proof-of-concept, with results that need to be confirmed in a larger sample of autistic individuals.

neuroscience↗

bioRxiv2023

Long-Run Olfactory Enrichment Promotes Non-Olfactory Cognition, Noradrenergic Plasticity And Remodeling Of Brain Functional Connectivity In Aged Mice

Normal brain aging is accompanied by functional and structural changes, leading to cognitive decline. A high level of cognitive stimulation during life is associated with improved cognitive performances in elderly, forming the so-called cognitive reserve whose cellular mechanisms remain largely unknown. Noradrenaline has been proposed as a molecular link between environmental stimulation and the constitution of the cognitive reserve. Taking advantage of the ability of olfactory stimulation to trigger noradrenaline release, we used repeated olfactory enrichment sessions distributed over the mouse lifespan to enable the cognitive reserve buildup. Mice submitted to lifelong olfactory enrichment whether started in early or late adulthood, displayed improved olfactory discrimination at late ages. Interestingly, benefits extended to spatial memory and cognitive flexibility and olfactory and non-olfactory cognitive performances correlated with increased noradrenergic innervation in the olfactory bulb and dorsal hippocampus. Finally, using c-Fos mapping and connectivity analysis, we reported task-specific remodeling of functional neural networks in aged mice with increased network specialization or enlargement in an olfactory discrimination or a spatial memory task respectively. We thus propose long-run olfactory enrichment as a mouse model of the cognitive reserve buildup relying on plasticity of the noradrenergic system and network remodeling to promote better cognitive aging.

neuroscience↗

bioRxiv2020

Norepinephrine, olfactory bulb and memory stability

Memory stability is essential for animal survival when environment and behavioral state change over short or long time spans. The stability of a memory can be expressed by its duration, its perseverance when conditions change as well as its specificity to the learned stimulus. Using optogenetic and pharmacological manipulations, we show that stability of an odor-reward association can be modulated by noradrenergic inputs to the first olfactory network, the olfactory bulb. We show that while manipulations of noradrenaline during an odor-reward acquisition have no acute effects, they impact learning flexibility as well as the duration and the specificity of the memory. We use a computational approach to propose a proof of concept model showing that a single, simple network effect of noradrenaline on olfactory bulb dynamics can underlie these seemingly different behavioral effects. Our results show how acute changes in network dynamics can have long term effects that extend beyond the network that was manipulated.

neuroscience↗