Measurements and Modeling of the Hemodynamic Response in the Human Brain

presented by Dr David Ress, Baylor College of Medicine where he is the Technical Director of the Center for Magnetic Resonance Imaging.
Abstract: The human brain exhibits a close relationship between neuronal electrical activity and blood flow. The phenomena, functional hyperemia, is the basis for functional magnetic resonance imaging (fMRI). In particular, a brief (~2 s) period of electrical activity evokes a stereotypical fMRI response that is often called the hemodynamic response function (HRF). Our laboratory has developed experimental methods, consisting of an audiovisual stimulus together with a speeded task, to evoke reliable HRFs across the majority of cerebral cortex in a single, hour-long fMRI scanning session. The resulting spatial pattern of response amplitudes is very similar across subjects. In healthy young subjects, the temporal dynamics of the HRFs vary only modestly across cortex. However, the dynamics show significant changes with aging possibly associated with cardiovascular changes. We have also developed a simple model for the HRF based on a linear network approximation to the vasculature, coupled with a 1.5D convection-diffusion treatment of oxygen transport. The model provides a quantitative interpretation of the HRF in terms of blood flow and cerebral oxygen metabolism. Our goal is to utilize these experimental and modeling methods as a means to diagnose various forms of brain pathology.
Speaker(s): David Ress,
Agenda:
presentation: Measurements and Modeling of the Hemodynamic Response in the Human Brain
speaker:
Dr David Ress, Baylor College of Medicine where he is the Technical Director of the Center for Magnetic Resonance Imaging
Virtual: https://events.vtools.ieee.org/m/353426