Grant: Discovery Grants Program - Individual

Summary: Functional Magnetic Resonance Imaging (FMRI) and Event-Related Potential (ERP) recordings represent two methodologies to study brain function. Although commonly used many questions remain as to what is being measured. The aim of this study is to better understand the characteristics of the sources being measured with each modality, their correlation, their different sensitivities and to demonstrate the complementary nature in assessing brain function. In the first series of experiments we will systematically test ERP inverse solution and improve our means of comparing and integrating ERP and FMRI imaging results. In the second series of experiments we will measure FMRI and ERP in both normal subjects and patients to explore to what extend the localization as found by ERP and FMRI is and behaves similarly when stimuli are modified or suppressed because of defects in the visual system in one eye. This will solidify our understanding of how ERP and FMRI source locations are linked. In the final series of experiments we will further explore particular aspects of the FMRI signal (negative BOLD) signal in response to visual stimuli to better understand the connection between this signal and the ERP and positive BOLD source locations. Significance: Imaging active sources in the brain in response to visual stimuli with both EEG and FMRI leads to a better understanding of the interaction of these two modalities, their utility and consequently brain function. Students trained through this research are in demand as medical physicists and neuroscientists.