Calendar

ECE PhD Prospectus Defense: Ting Xie

Starts:
12:00 pm on Wednesday, May 14, 2025
Ends:
2:00 pm on Wednesday, May 14, 2025
Location:
PHO 442, 8 St Mary's St.

Title: Theoretical and computational modeling of myelin structure degradation

Presenter: Ting Xie

Advisor: Professor Irving Bigio

Chair: Professor Lei Tian

Committee: Professor Irving Bigio, Professor Jerome Mertz, Professor Lei Tian, Professor Darren Roblyer.

Google Scholar Link: https://scholar.google.com/citations?user=GIRkZCIAAAAJ&hl=en

Abstract: The structural anisotropy of myelin in brain tissue induces optical birefringence, enabling quantitative birefringence microscopy (qBRM) as a powerful tool for assessing neurodegenerative diseases. While various polarized light imaging techniques have been used to study myelin breakdown, wide-field BRM offers the necessary resolution and sensitivity to detect microstructural changes in human brain tissue, with high throughput. As a label-free method, BRM quantifies retardance, transmission, and axonal directionality; however, its widefield modality limits optical sectioning, leading to out-of-focus light and reduced sensitivity to subtle myelin alterations in denser media. This study explores the optical properties of myelin, the potential for optical tomography with BRM, and 3D rendering of myelinated fibers, with three specific aims:

  • Aim 1: Develop a method to measure the absolute value of birefringent refractive index difference of myelin sheaths, using qBRM in rhesus macaque brain tissue, as a surrogate for human brain. This enables quantification of myelin volume fraction in white matter, providing a tool to assess myelin loss in neurodegenerative diseases.
  • Aim 2: Enhance the optical sectioning of wide-field BRM images using structured illumination techniques, improving contrast and resolution for clearer imaging of myelin breakdown and axon architecture—critical for understanding neurodegenerative disease progression.
  • Aim 3: Develop simulation and experimental techniques to generate 3D renderings of myelinated fibers in human and/or monkey brain tissues, demonstrating their applicability to connectivity mapping.

    Preliminary results on birefringence measurements, optical sectioning, and 3D simulations are presented, offering deeper insights into myelin structure and its role in neurodegenerative disease progression.