University of Massachusetts Amherst

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Iris Burns



Undergraduate Research Award


Iris Burns is an undergraduate research assistant in the Department of Psychological and Brain Sciences. Under the mentorship of Agnès Lacreuse, her current research is focused on attentional biases in aging marmosets regarding emotional stimuli through a cognition test called the Dot-Probe task. Her thesis will continue to investigate the cognition of aging marmosets and how their sex and hormonal differences contribute to levels of cognitive decline.


The dot-probe task tests attentional biases in aging marmosets. Using a touchscreen interface, the Dot-Probe Task measures attention and is designed to probe attentional biases for emotional stimuli. Marmosets are trained to touch a dot on the screen that appears behind the display of one of two stimuli (one positive or negative emotional image and one neutral image). If the marmoset touches the dot, they receive a reward. Their performance is based on the amount of time they take to touch the dot and data is analyzed according to different hormonal treatment groups. The treatment groups are a vehicle group, a Letrozole group, and a Letrozole + DHED group. Letrozole prevents the synthesis of estrogen and simulates some of the effects that women go through during menopause. DHED is a brain-selective estrogen that has been shown to enhance the cognitive functions of aging rodents and has therapeutic potential regarding menopause and Alzheimer’s disease.

This research is important because it helps analyze cognition under hormonal treatments. Additionally, menopause is an inevitable experience for all women at some point in their lives, and it is during and after this phase that numerous negative cognitive effects appear. Many of these negative cognitive effects are caused by the reduction of estrogen and can make women more prone to cognitive problems that are commonly associated with the onset of Alzheimer’s disease. Our research aims to reveal that marmosets in the simulated menopause group with the DHED treatment exhibit a reduced rate of cognitive decline over a set amount of time. After subsequent and further research, DHED may serve as an effective treatment that can moderate age-based cognitive decline.

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