Date of Award

Summer 2002

Document Type

Thesis - Restricted

Degree Name

Master of Science (MS)


Biomedical Engineering

First Advisor

Ropella, Kristina M.

Second Advisor

Prieto, Thomas E.

Third Advisor

Liebenthal, Einat


Functional neuroimaging of the brain is a field that has rapidly expanded in recent years. The main goal of functional neuroimaging is to map the activity of the living brain in space and time. The ideal means for measuring brain cell activity would be the direct and invasive electrical recording of the membrane potentials of individual neurons. However, this cannot be easily achieved with humans for obvious reasons. Instead, noninvasive methods must be applied, and all of these methods have various limitations. The two main approaches for noninvasive functional neuroimaging are through either metabolic and vascular methods or electrophysiological methods. Electroencephalography (EEG) and functional Magnetic Resonance Imaging (fMRI) are two techniques used to analyze brain function. EEG is a technique that measures signals which arise as a summation of electrical events in individual brain cells. FMRI is an imaging technique, which not only provides images of structure, but also provides information on which structures participate in different functions of the body. FMRI involves measuring changes in oxygen levels in the brain, which is an indicator of blood flow and a property of cortical activity. These two techniques have complimentary strengths, and they are now being used simultaneously to try and provide a more powerful tool in brain research. Functional MRI is a technique that has good spatial resolution but poor temporal resolution, whereas EEG has good temporal resolution but poor spatial resolution. The combination of these two techniques is promising, but severe interference arises between them because both techniques are based on electromagnetism. The EEG recording system has a minimal influence on the functional MR images, however the signals obtained from the EEG recording system are severely affected by the MR environment. The Ballistocardiogram Artifact is an MR-induced artifact which dominates the EEG signal and makes the acquisition of electrophysiological information difficult to obtain.The main objective of this research is to reduce these MR-induced artifacts in order to determine if it is viable to obtain auditory event-related potentials acquired in the MR-environment, and furthermore to determine if a mismatch negativity elicited in response to the deviant stimuli can be detected. More specifically, we aimed to...



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