Combination of Multiparametric MRI and Electrophysiology for the Development of New Biomarkers in Spinal Cord Diseases

The spinal cord is a common site for the development of several neurodegenerative neurological disorders (spinal muscular atrophy or SMA, amyotrophic lateral sclerosis or ALS, X-linked spinal bulbar muscular atrophy or SBMA). In different proportions, these diseases involve axonal loss in large funiculi of the spinal white matter, their demyelination, and loss of ventral horn motor neurons or motoneurones of the spinal gray matter. The lack of specific biomarkers of these macro and microscopic spinal damages, makes it difficult the differential diagnosis and monitoring of these diseases. Techniques to explore non-invasively the human central nervous system, such as magnetic resonance imaging (MRI) and electrophysiology, are potential tools to extract specific biomarkers of spinal damages. However, imaging techniques are still poorly developed at spinal level for technical (specific antennas), anatomical (size of the spinal cord, vertebrae) and physiological reasons (cardio-respiratory movements). However, recent advances in the field of spinal cord imaging allowed to extract quantitative data on neuron loss, axonal degeneration and demyelination in different spinal pathologies whether degenerative (ALS or SMA) or traumatic (SCI). Correlations were found with clinical data, and in ALS patients, the changes in MRI metrics over time paralleled the functional deterioration. The electrophysiological techniques are used since a long time, leading to a good knowledge of the neurophysiology of human spinal cord. In addition, electrophysiology indirectly provides data at a microscopic scale, providing information on the excitability of spinal neural networks and giving an estimate of the amount of functional neurons. By combining these techniques for the investigation of human spinal cord in vivo, the goal is to extract new biomarkers using as study models, diseases of the spinal cord affecting differentially the white and the gray matter (SMA, SBMA and ALS). At first, ne