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\section{Background}  \subsection{fMRI in Multiple Sclerosis} Functional MRI tasks have shown regions of abnormal activity from MS patients compared to controls \cite{cader2006reduced}, suggestive of adaptive or maladaptive mechanisms to damage. In a study of lower motor disease severity and its relationship to task activity, researchers found that increased ipsalateral activation on a motor task \cite{} was related to decreased lower motor disease severity. This could signify that neurons are recruited from the part of the corticospinal tract that does not cross over.  However, these task-fMRI  results may be influenced by performance in the scanner \cite{rsfmri_ms_review}.Therefore \cite{rsfmri_ms_review}, and therefore,  resting state fMRI-derived metrics are more standardized and are easier preferred due  to acquire, better standardization,  especially for patients with higher disability status. The BOLD fluctuations of the brain at rest are organized in networks, which are synchronous, spatially distinct regions. In healthy controls, Yeo and colleagues found 7 stable networks, with each network responsible for different tasks \cite{yeo2011organization}. These networks are the visual, sensorimotor, dorsal attention, ventral attention, limbic, frontoparietal and the default mode. Of these networks, the default mode network (DMN) has been the most studied (for a review, see \cite{raichle2007default}). Alterations in the default mode network have been detected in many neurological and psychiatric diseases, such as Alzheimers \cite{greicius2004default}, depression \cite{sheline2009default}, schizophrenia\cite{garrity2007aberrant}, Parkinson's disease \cite{van2009dysfunction}, and multiple sclerosis \cite{bonavita2011}.   My preliminary research has shown that increased functional connectivity between nodes in the default mode network and the motor strip is correlated with increased upper motor disability. Funcitonal connectivity combined with T2 lesion load explains 40\% of the variance in the nine hole peg test (a measure of upper motor disability) score in our cohort of MS patients.  \subsection{Neurophysiology My preliminary research has shown that functional connectivity, combined with T2 lesion load, explains 40\% of the variance in the nine hole peg test (a measure of hand dexterity) score in our cohort of MS patients. This metric was based on increased functional connectivity between nodes in the sensorimotor strip and the precuneus and posterior cingulate, which are important hubs  of Multiple Sclerosis} the default mode network. It is possible that the posterior medial cortex (precuneus and posterior cingulate gyrus), plays an important role in functional adaption for upper extremity motor disability. However, differential connectivity strengths were also detected between the sensorimotor cortex and the frontoparietal, visual, and dorsal attention networks. The frontoparietal and dorsal attention networks are involved in association, executive control, and visuospatial integration. Therefore, poor performance on the nine hole peg test may not be fully attributable to motor pathway damage alone, but rather could be a result of damage to the visual integration pathways.   In order to understand the relationship between functional MRI networks and upper-extremity motor disability, metrics that are more specific to motor pathway damage need to be studied. I propose to collect two metrics that are less dependent on visuospatial ability. These include the finger tapping test and central motor conduction time. The finger tapping test is a simple and reliable measure of upper-extremity motor speed. In MS patients, it was shown to be below average in 55\% of patients on the non-dominant and 65\% below average for the non-dominant hand \cite{}.  Electrophysiological measures, such as the motor evoked potential (MEP) are used for the diagnosis of MS and as a measure of dysfunction of the corticospinal tract \cite{kallmann2006early}. Increased central motor conduction times (CMCT) are seen in MS patients, which is a result of demyelination from the disease, conduction block, or axonal destruction \cite{fuhr2001evoked}. The motor evoked potential (MEP) and visual evoked potential (VEP) have been shown to be strongly predictive of changes in MS disability a full 14 years after the initial measurements \cite{schlaeger2012prediction}, with a spearman's rank correlation of $\rho = 0.69$.