Superposition of activations of SWI and fMRI acquisitions of the motor cortex

Functional Magnetic Resonance Imaging (fMRI) has been an important tool for the understanding of the neural basis of cognition and behavior in the past years. Most studies rely on changes in the blood oxygenation level dependent (BOLD) contrast, to get an insight of the metabolic activity of specific areas in the brain, yet the particular physiological phenomena being measured is not fully understood. The present work aims to identify the correlation between fMRI signals and the venous structures being activated during the same tasks. By co-registering fMRI, Susceptibility Weighted Imaging (SWI) and T1 weighted images we can highlight the specific areas being activated during a behavioral task and correlate the fMRI signal to the spatial location of the active vein closest to the activated cluster. The SWI sequence activation is derived from the subtraction of images, obtained during rest and behavioral tasks, being able to provide images of the venous structures activated during a task. Although most of the used SWI subtraction data was too noisy, the results were quite promising. For a particular case, we managed to apply registration techniques to the fMRI, SWI and T1 weighted image sets, showing coherence between fMRI activation of the motor cortex and the vein identified in the SWI. Further development of the technique under better controlled conditions is required, in order to reduce the noise and deal with the difficulties we encountered. We hope to add extra information to the problem of the physiology mechanisms that underlie behavioral brain activation.