The density of doublecortin cells in the piriform cortex is affected by transition to adulthood but not first pregnancy in mice

Abstract

Motherhood is a critical period modulating behavioural changes to favour survival in mammals. In mice, olfaction is a key driver of social behaviours, and adult neurogenesis in the olfactory bulb is modulated at this stage, contributing to pup recognition. The primary olfactory cortex, known as the piriform cortex, contains a special population of neurons of embryonic origin which continues expressing immature markers such as doublecortin (DCX) in young and adult mice, and present a long period of protracted maturation and integration into the circuit as the animal ages. While these immature neurons are considered a potential source of plasticity, their precise role and whether motherhood affects their maturation rate remains unclear. To investigate this question, we analysed the expression of DCX in prepubescent vs. young adults, in virgin vs. pregnant and in pup-sensitized virgins vs. lactating female mice. We found that the density of DCX cells sharply decreased in the piriform cortex with age, previously demonstrated as a proxy of their integration as glutamatergic neurons by contrast, pregnancy and lactation failed to significantly alter the density of these cells. To further analyse how motherhood could affect DCX-ir cells, we co-labelled DCX cells with NeuN, an archetypical marker of mature neurons. We did not find significant differences in the percentage of double-labelled cells nor in features related to maturation like number of neurites or main diameter in lactating dams as compared to pup-sensitized virgin females. Our results suggest that the first pregnancy does not significantly affect the differentiation of immature neurons of the piriform cortex.

Bibliographic Information