Hyun Koo Chung

MS Thesis Defense Presentation

Date: Oct 18th, 2017

Time: 9:15am

Location: Emory HSRB 182

Committee Members:

Shella Keilholz, PhD (Advisor, BME Emory-GT)

Dieter Jaeger, PhD (Bio/BME - Emory)

Eric Schumacher, PhD (Psy - GT)

Title:

Effects of Quasi-periodic Pattern Regression on BOLD Signals Correlated with Infraslow and Broadband Electrophysiology

Abstract:

Functional MRI (fMRI) have provided information on the brain to understand neural networks, disorders, and cognitive performance. Recent studies have focused on fMRI during resting state conditions to understand spontaneous spatiotemporal dynamics of the brain. To supplement BOLD signals, resting state fMRI studies have been paired with simultaneous recording of electrophysiology data, a method to provide a direct measure of neural activity. Recent studies have focused on understanding the infraslow frequencies (<1Hz) to understand large scale spatial and temporal dynamic. Dynamic analysis of the infraslow frequencies have shown semi-reoccurring BOLD spatiotemporal patterns, which have been defined as quasi-periodic patterns (QPP). This study expands on the previously published data acquired using simultaneous fMRI and local field potential (LFP) recordings to understand the effects of removing the quasi-periodic patterns from the BOLD signal. Furthermore, this study focuses on the effects of quasi-periodic patterns regression on the relationship between BOLD and higher frequencies between 1 and 100Hz. This results show that QPP regression from the BOLD signal reduces the correlation to all LFP frequencies. The study suggests that infraslow and higher frequency neural activities play a role in coordinating the large scale networks observed through the quasi-periodic patterns.