Differential Effects of Estrogen on Memory Processes and Learning Strategies: A Selective Review of Animal Studies

Abstract

estrogen has differential effects on learning and memory. The direction of these effects depends on a variety of factors including the type of memory process, task specific demands, dose and time course of treatment. While some processes, including working memory, spatial memory and place learning, are improved in high estrogen conditions, other processes such as amygdala-dependent associative memory, reference memory and response learning are impaired. Furthermore, learning strategy is sensitive to the effects of estrogen. specifically, high estrogen conditions promote the use of a hippocampus-dependent strategy, while low estrogen levels bias learning towards a response strategy. In humans, the evidence for effects of estrogen on cognitive function is controversial and the mechanisms of action are not fully understood. This review will discuss major findings from animal studies, highlighting the modulatory effects of estrogen on learning and memory, possible neurobiological mechanisms underlying these effects and the implications of these findings for future investigations of the cognitive effects of estrogen in humans.