Lauren Daley
BME PhD Defense Presentation

Date: 2026-11-11
Time: 3:00pm
Location / Meeting Link: HSRB Auditorium or https://emory.zoom.us/j/99567578053

Committee Members:
Shella Keilholz, PhD (advisor); Lynn Marie Trotti, MD; John Oshinski, PhD; Candace Fleischer, PhD; Vince Calhoun, PhD


Title: Cross-species characterization of spatiotemporal patterns from rs-fMRI data across states of wakefulness

Abstract:
Functional MRI (fMRI) is vitally important to the field of neuroscience; several key findings cite fMRI studies as primary evidence to support those claims. We understand fMRI to represent a proxy of neural activity, not a true capture of real-time neuronal activation, but a time-lagged hemodynamic response. fMRI signal, both resting-state and task-based/stimulation-evoked, has been acquired in many species, finding several preserved resting-state networks and task responses. However, there are still key gaps in cross-species fMRI experiments, including fully elucidating how arousal or wakefulness state impacts the resultant signal, establishing robust and reproducible awake mouse protocols, and the ongoing debate of time-averaged versus time-varying methods. This thesis employs several fMRI datasets spanning across species (human, mouse), field strength (3T, 9.4T), acquisition sequence (Echo Planar Imaging, EPI; Zero Echo Time, ZTE), analysis method (functional connectivity, FC; quasi-periodic pattern, QPP; complex principle component analysis, CPCA), and, most importantly, across state of wakefulness (awake, asleep, anesthetized). Using clinical data from the Emory Sleep Center that spans across diagnostic criteria for hypersomnolence disorders, I first establish the human arm of this axis. I then developed a robust protocol for acquiring awake mouse fMRI data, and from this data, established the mouse arm of this axis. This awake mouse fMRI provides the cross-species homologue for awake, resting-state human fMRI, and was tested via a feasibility study of the MitoPark mouse model. Upon completion of these individual projects, I then identified preserved resting-state and large-scale brain networks, notably the Default Mode Network (DMN), and Somatomotor Network (SMN). These network interactions acted as the basis for the proposed cross-species axis of arousal, finding tightly-coupled relationships between DMN and SMN strength and activation with state of wakefulness. This axis will hopefully act as a guide for researchers in designing future fMRI experiments, particularly pre-clinical experiments aimed at translational research.