Title: Investigating Brain Microstructure in Humans Using Advanced Diffusion Weighted Imaging.
Abstract: The brain goes through many structural changes because of age and disease, resulting in a variety of cognitive and behavioral deficits. However, studying these physical changes, in vivo and non-invasively, is quite challenging- especially in humans. Diffusion weighted imaging, a kind of Magnetic Resonance Imaging (MRI) that tracks water molecules in the brain, has been immensely valuable in understanding white matter degeneration with age. However, standard diffusion imaging faces many caveats: Tensors, the mathematical model traditionally used to analyze diffusion signals, aren’t specific or sensitive enough to detect explicit microstructural features, and cannot be effectively used to study more complex structures, like most gray matter regions. Recent advances in diffusion imaging analysis might be able to overcome some of these challenges and be better equipped to study the cytoarchitectural origins of cognitive decline. My research considers two modern diffusion analysis techniques- Neurite Orientation Dispersion and Density Imaging (NODDI), and Constrained Spherical Deconvolution (CSD), and proposes to:
1) Ascertain that these methods can capture more sensitive measures of age-related changes in the microstructure of the human medial temporal lobe and determine its relationship with verbal memory.
2) Identify what the metrics produced by these methods neurobiologically correspond to and model cell type specific relationships
3) Determine interventions in animal models and humans that could influence these metrics and consequently motivate behavioral outcomes.