Working memory for emotional facial expressions: role of estrogen in humans and non-human primates.

In recent years, numerous studies focusing on the role of sex steroid hormones on neuropsychological functions have been reported. The influence of estrogens on cognition can be explained by the widespread presence of estrogen receptors (ERs) in limbic and cortical areas, and the modulator role of estrogens on numerous neurotransmitter systems. There is a great deal of evidence suggesting that estrogen can enhance memory processes and improve performance in working memory (WM) tasks, including face-tasks, delayed matching-to-sample (DMTS) and delayed non-matching-to-sample (DNMTS). The modulator effects exerted by estrogens are complex and may vary according to task, gender, and phase of the menstrual cycle. For many years, physiological hormonal fluctuations during the menstrual cycle, postpartum, and menopause have been said to influence mood, cognition, and affective disorders. In addition, it has been hypothesised that estrogens have a protective role in schizophrenia and Alzheimer's disease (AD). Taking into account that women's performance in memory tasks can also fluctuate with circulating hormone levels across the menstrual cycle, data related to the cognitive performance in a WM task for emotional facial expressions were reported. The findings described in this review can contribute to clarifying the role of the steroid hormone estrogen in the modulation of cognitive functions, particularly memory, and indicate the possible usefulness of applying a new paradigm, employing a DNMTS task with emotional facial expressions, in studies focused on emotional WM in relevant models of nonhuman primates. Such data could also represent a useful tool in individualizing effective therapy for the treatment of disturbances linked to menstrual cycle phases and menopause in women.