Xinyi(Jemma) Jiang
BME PhD Proposal Presentation

Date: 2026-11-04
Time: 1pm-3pm
Location / Meeting Link: Clough Undergraduate Learning Commons, room 127; https://emory.zoom.us/j/91475318334

Committee Members:
Annabelle Singer, PhD (Advisor) Levi Wood, PhD Ming-Fai Fong, PhD Joseph Manns, PhD Jessica Bolton, PhD

Title: Microglial Regulation of Hippocampal Neural Activity During Spatial Learning

Abstract:
Spatial learning depends on coordinated activity in the hippocampus, a brain region essential for learning and memory. During brief bursts of activity called sharp-wave ripples, hippocampal neurons reactivate representations of past experiences, supporting memory consolidation. Microglia, the brain’s resident immune cells, interact with neurons and influence network activity, yet whether they contribute to the hippocampal changes required for new spatial learning remains unknown. Establishing their role in healthy animals will provide a foundation for understanding memory impairment in Alzheimer’s disease, where both microglial function and hippocampal activity are altered. This project will determine how microglia contribute to behavioral, network, and molecular changes during spatial learning in healthy adult mice. I hypothesize that microglia are engaged during learning and are necessary for the coordinated neuronal activity and gene-expression changes that support acquisition of new spatial information. Preliminary findings suggest increased expression of CD68, a marker associated with microglial activation and phagocytic activity, in hippocampal area CA3 after exposure to new reward locations. Behavioral findings also suggest that systemic microglial depletion may impair new spatial learning. To test this hypothesis, mice will first learn reward locations on a familiar virtual-reality track and then receive a microglia-depleting treatment directly into the hippocampus or a vehicle control. Recordings from hippocampal areas CA1 and CA3 during familiar-track performance and subsequent novel-track learning will assess spatial representations, sharp-wave ripple properties, and reactivation of newly learned spatial information. Bulk RNA sequencing of the hippocampus will identify learning-associated gene-expression changes and determine how depletion alters neuronal plasticity programs and responses in other brain cell populations. Vehicle-treated mice remaining on the familiar track will provide a comparison for identifying molecular responses associated with new learning. I predict that microglial depletion will preserve familiar-task performance but impair novel-track learning, reduce ripple-associated reactivation, and attenuate learning-associated neuronal plasticity programs. By connecting cellular responses with hippocampal activity and behavior, this work will test whether microglia actively support spatial learning and identify candidate pathways for future investigation of memory dysfunction in Alzheimer’s disease