The Paris Brain Institute is a research center on diseases of the nervous system located in the Pitié-Salpêtrière Hospital in Paris. By bringing together patients, doctors, and researchers in one place, the aim of the ICM is to enable the rapid development of treatments for nervous system injuries in order to improve the lives of patients. I worked in the Mov'it team, which researches problems with neuronal networks in movement disorders. My project was the analysis of differences between the fibers that connect different regions of the brain, also known as white matter fibers, in patients with myoclonus dystonia.

This project was a 3 month long research internship at the Paris Brain Institute in the Pitié-Salpêtrière Hospital in Paris, France. The research that I conducted is part of a larger study being conducted to better understand the underlying causes of and brain involvement in myoclonus dystonia (M-D).

Myoclonus dystonia is a movement disorder characterized by a combination of rapid, brief muscle contractions (myoclonus) and/or sustained twisting and repetitive movements that result in abnormal postures (dystonia). The myoclonus jerks typical of M-D most often affect the neck, trunk, and upper limbs. 

The prevalence of myoclonus-dystonia in Europe is estimated to be 1 in 500,000 individuals. Its prevalence elsewhere in the world is unknown. As such, it is quite rare and has yet to be studied in more depth. It was exciting to be able to focus on addressing such a unique disorder for my project. I knew that any work that I did would be a step in the right direction in helping those who live with myoclonus dystonia. While it may not be as prevalent as some other movement disorders, such as Parkinson’s disease, the people who do live with Myoclonus dystonia do face significant challenges socially, professionally, and otherwise in their lives. Additionally, the onset of Myoclonus dystonia is early; usually symptoms start presenting themselves in the late teens and early 20s. As such, myoclonus dystonia is a disorder that patients live with for a vast majority of their lives. The hope is that by increasing research conducted on M-D, we grow a larger knowledge base and are able to develop clinical solutions.

At the beginning of my project, we suggested the hypothesis that there are microstructural abnormalities in the white matter tracts that depart from the cerebellum which may lead to the development of myoclonus dystonia. The goal of the study was to determine, by comparing patients with myoclonus dystonia and healthy volunteers using structural connectivity analysis, whether white matter abnormalities exist in the tracts that connect the cerebellum with other structures in the brains of patients with M-D. 

Most of the work that I did for my project was done on my own. I worked very closely with my direct supervisor, which was helpful as I had many questions throughout the process. A majority of my work was done using FSLeyes, which is widely used in the field of neuroimaging research and is particularly useful for analyzing data from functional MRI (fMRI), diffusion tensor imaging (DTI), and structural MRI (sMRI) studies. It can help researchers to better understand brain structure and function and to identify abnormalities or changes in brain activity associated with various neurological or psychiatric conditions. I was analyzing DTI data gathered by my supervisor using FSLeyes. As I was analyzing brain images and looking for statistically significant differences in white matter of the brain, most of my work took place in the form of coding. I thus spent most of my time working on my computer, while also attending some lab meetings to share what we are working on. 

Twenty-one DYT-SGCE and 25 control subjects were scanned with 3-Tesla MRI to compare fractional anisotropy, mean diffusivity, orientation dispersion index, isotropic volume fraction, and intracellular volume fraction between groups. The imaging was subsequently analyzed with tract-based spatial statistics (TBSS), looking at white matter tracts in the brain as a whole. After this, probabilistic tractography was carried out to extract the motor cerebello-thalamic pathway (MCTP). MCTP was compared between groups using TBSS. A correction using TFCE was used and a threshold of 0.05 was set.

Image Credits: https://institutducerveau-icm.org/en/