Hailey Beaty, “Estradiol Influences Memory Formation Via Prefrontal Cortex Mechanisms”
Mentor: Karyn Frick, Psychology
Poster #93

The purpose of this project is to study the role of brain estradiol synthesis and prefrontal cortex activity during memory formation, with the long-term goal of understanding and treating memory decline. Memory deficits are often associated with dysfunction in the prefrontal cortex and there is a need to understand the function and physiology of this region during memory formation. The hormone 17-β- estradiol can regulate synaptic plasticity and enhance the consolidation of memories such as spatial memory and object recognition. However, little is known about the involvement of E2 in areas in mediating memory formation outside of the hippocampus. Letrozole has been shown to cause cognitive impairments, thus we hypothesized that de novo E2 synthesis in mPFC is likely necessary for object recognition memory formation. Letrozole-infused mice exhibited impaired OR and OP memory consolidation, suggesting that E2 synthesis in mPFC is essential during memory consolidation. To determine effects of letrozole on neuronal activity using fiber photometry, a method for measuring intracellular calcium levels in awake behaving animals. Intracellular calcium is a vital factor in initiating synaptic plasticity and can serve as an indirect measure of brain activity. GCaMP, a genetically encoded calcium indicator, allows for in vivo visualization of changes in intracellular calcium via fiber photometry. By recording calcium activity in a population of neurons, we can study brain activity during and after memory formation to supplement our ongoing studies of estrogenic regulation of memory. Fiber photometry was performed during training, 30 minutes after training, and testing phases of object recognition. Analysis of fiber photometry data is ongoing, and we expect to examine the effect of gonadal hormones on mPFC calcium activity during object training and testing. We hypothesize increased mPFC activity in the SHAM group during object training and testing, and greater activity during recognition of familiar objects.