Sex differences in chronic stress effects on cognition in rodents

Abstract

Chronic stress causes deleterious changes in physiological function in systems ranging from neural cells in culture to laboratory rodents, sub-human primates and humans. It is notable, however, that the vast majority of research in this area has been conducted in males. In this review, we provide information about chronic stress effects on cognition in female rodents and contrast it with responses in male rodents. In general, females show cognitive resilience to chronic stressors which impair male cognitive function using spatial tasks including the radial arm maze, radial arm water maze, Morris water maze, Y-maze and object placement. Moreover, stress often enhances female performance in some of these cognitive tasks. Memory in females is not affected by stress in non-spatial memory tasks like recognition memory and temporal order recognition memory while males show impaired memory following stress. We discuss possible bases for these sex-dependent differences including the use of different strategies by the sexes to solve cognitive tasks. Whether the sex differences result from changes in non-mnemonic factors is also considered. Sex-dependent differences in alcohol and drug influences on stress responses are also described. Finally, the role of neurally derived estradiol in driving sex differences and providing resilience to stress in females is shown. The importance of determining the nature and extent of sex differences in stress responses is that such differences may provide vital information for understanding why some stress related diseases have different incidence rates between the sexes and for developing novel therapeutic treatments.

Let’s call the whole thing off: evaluating gender and sex differences in executive function

“…The most typical measure for this task is the total number of arm entries to collect all the available food. Males have repeatedly been shown to use a lower number of total arm entries to complete this task [85][86][87][88][89], but there have also been a number of papers showing no sex difference in this measure [90,91]. This result has often been interpreted to mean that males are better at maintaining in mind which arms have already been visited, and thus that males have an advantage in working memory in general.…”

The α7 nicotinic acetylcholine receptors regulate hippocampal adult-neurogenesis in a sexually dimorphic fashion

“…Multiple previous studies show an association between levels of adult neurogenesis and performance in tasks measuring pattern separation, spatial discrimination, or cognitive flexibility (Clelland et al 2009; Cushman et al 2012; Hollands et al 2017; Pan et al 2012; Sahay et al 2011). Previous studies in rats and voles have shown the hippocampus to be a sexually dimorphic structure (Galea 2008; Luine et al 2017). For instance, estrogen increases neurogenesis during proestrus in female rats (Tanapat et al 1999).…”

Cognitive training increases dendritic arborization in the dorsal hippocampal CA1 and CA3 neurons of female and male Long–Evans rats

“…Nonetheless, similar to previous studies of Sprague Dawley and Fischer 344 rats (Spivey et al, ; Tropp & Markus, ), the present study found that female Long–Evans rats exhibited increased levels of locomotor activity in the open‐field test relative to the levels of male rats. Female rats have generally been observed to be more active than male rats (Luine, Gomez, Beck, & Bowman, ), possibly because male rats are more anxious and explore their environment more thoroughly, seeking places of refuge, than females or because they use different strategies than females do to explore novel environments (Alstott & Timberlake, ; Luine et al, ; Tropp & Markus, ).…”