Aniko Korosi

Coercive mating is a sexual selection strategy that is likely to influence female cognition. Female harassment levels have been linked to altered brain gene expression patterns and brain size evolution, suggesting females may respond to coercive mating by investing energy into “outsmarting” males. However, females exposed to coercive males have decreased foraging efficiency and likely increased stress levels, suggesting their brain function might instead be impaired. While it is therefore likely that coercive mating impacts female cognitive abilities, a direct test of this idea is currently lacking. In this study, we investigate the impact of coercive mating on female spatial memory and cognitive flexibility in a species with prevalent coercive mating. We compared the performance of female porthole livebearers ( Poeciliopsis gracilis ), which had been previously housed alone or with a coercive male, in both a spatial food localization task and a reversal learning task. While we found that both single and paired fish exhibited high proficiency in learning both tasks, we found no differences in learning ability between females that had or had not experienced coercive mating. In addition, our study found that the presence of a coercive male had no impact on female fecundity, but did influence female mass and standard length. Several studies have assumed that the presence of males, particularly coercive males, may affect the cognitive performance of female fish. However, our study shows that for some species females adapted to coercive mating regimes may be unaffected by male presence with regards to some cognitive tasks.

INTRODUCTION Early‐life stress (ES) increases the risk for Alzheimer's disease (AD). We and others have shown that ES aggravates amyloid‐beta (Aβ) pathology and promotes cognitive dysfunction in APP/PS1 mice, but underlying mechanisms remain unclear. METHODS We studied how ES affects the hippocampal synaptic proteome in wild‐type (WT) and APP/PS1 mice at early and late pathological stages, and validated hits using electron microscopy and immunofluorescence. RESULTS The hippocampal synaptosomes of both ES‐exposed WT and early‐stage APP/PS1 mice showed a relative decrease in actin dynamics‐related proteins and a relative increase in mitochondrial proteins. ES had minimal effects on older WT mice, while strongly affecting the synaptic proteome of advanced stage APP/PS1 mice, particularly the expression of astrocytic and mitochondrial proteins. DISCUSSION Our data show that ES and amyloidosis share pathogenic pathways involving synaptic mitochondrial dysfunction and lipid metabolism, which may underlie the observed impact of ES on the trajectory of AD.