E Science News -- Feeling a little sluggish and having trouble concentrating? Hormones might be to blame according to new research from Concordia University published in the journal Brain and Cognition. The study shows that high estrogen levels are associated with an inability to pay attention and learn – the first such paper to report how this impediment can be due to a direct effect of the hormone on mature brain structures. “Although estrogen is known to play a significant role in learning and memory, there has been no clear consensus on its effect,” says senior author Wayne Brake, an associate professor at Concordia’s Center for Studies in Behavioural Neurobiology. “Our findings, using a well-established model of learning called latent inhibition, shows conclusively that high estrogen levels inhibit the cognitive ability in female rodents.”