UCSF

Neurosurgery and Disconnection Syndrome research have a symbiotic relationship. The human brain is a staggeringly complex system, unique to each individual. Even at birth there is already incredible diversity to this network, upon which we add a lifetime of experiences, influencing our brain structure and function by the way we use it. One of the best ways to study such a variable and complex system is to see what happens when it is perturbed. Neurosurgical intervention presents a rare opportunity to interact with the human brain in a controlled environment and see what happens when transient or permanent interference occurs. In return, the lessons learned about the relationship between brain structure and function can guide surgical intervention to minimize the risk of surgical injury causing permanent functional deficits. The risk a person is willing to take on to a functional system is a very personal decision; to some people, motor or language function may be what makes life worth living and others are willing to risk deficits to treat a pathology more aggressively. Understanding what damage patterns result in deficits is key to empowering the patient to make these decisions.

The brain's white matter connections can be modeled with Diffusion-Weighted Magnetic Resonance Imaging (DW-MRI) Fiber Tracking (also called tractography), a process by which water diffusion is used to deduce pathways of axon bundles. Neurosurgical applications present particular engineering challenges due to a variety of factors influenced by both the pathology and intervention. This thesis details several tools developed to address these challenges including methods to quality-control tractography streamline datasets, a processing pipeline to model disconnections caused by surgical intervention, a method to translate tractography information to a format tractable for integration with radiation therapy planning, and a pipeline relating electrode stimulation to white matter connectivity. All of the code is open-source so that researchers can use these tools to conduct their own studies.