LONG TERM EFFECTS OF PERIPUBERTAL STRESS ON THE DIENCEPHALON OF FEMALE AND MALE MICE

Early life stress can cause profound and multifaceted effects on the brain, producing complex dysregulation across multiple circuits that can be predisposing factors for mental disorders. The unpredictable chronic peripubertal stress (PPS) is a well-stablished model of early chronic stress, in which animals are exposed to a series of unpredictable stressors between P28 and P42 on seven non-consecutive days. Interestingly, previous findings from our laboratory demonstrated that PPS induces a significant reduction in the volume of the thalamic reticular nucleus in adult female mice. To further investigate the impact of PPS on the diencephalon we analysed the volume of eight diencephalic nuclei, including several excitatory thalamic nuclei and the habenular nuclei. For this analysis, panoramic images were assembled to create composite image of brain sections on which volumetric analyses were performed. The results revealed a significant reduction in the volume of the lateral habenula and laterodorsal thalamic nucleus in stressed females. In contrast, we detected an increase in the anterodorsal nucleus of the thalamus of stressed mice, when analysing both sexes together or male mice, with a similar tendency in females. Together, these findings indicate that PPS induces region- and sex-specific structural remodelling within the diencephalon, which may underlie long-term effects of aversive experiences during early life. Future studies will examine how specific plasticity-markers may be altered in the lateral habenula of PPS mice and whether these changes are associated with glial alterations.