BME-IBSC PhD Defense Announcement for Antonia Šušnjar (J. Rispoli and T. Talavage, Co-Chairs) Everyone is invited to attend the public presentation beginning at 1:00 PM. Title of the Thesis Research: Clinical Applications of Magnetic Resonance Spectroscopy Date: April 11th Time: 1pm-3pm Place: Purdue Graduate Student Center, Room 105 Zoom link: https://purdue-edu.zoom.us/j/98032847567 Thesis Committee members: Dr. Joseph Rispoli, Major Professor, Co-Chair Dr. Thomas Talavage, Co-Chair Dr. Ulrike Dydak Dr. Uzay Emir Abstract: Magnetic resonance spectroscopy (MRS) is a non-invasive imaging technique that provides unique information about the biochemical composition of the human body. By excluding the overwhelming signals from water and fat, clinically relevant biomarkers such as lactate, N-acetyl aspartate, choline, creatine, glutamate/glutamine (Glx), gamma-aminobutyric acid (GABA), glutathione, and myoinositol can be reliably quantified. MRS has diverse applications in investigating the metabolic window of a wide range of biochemical processes. Here, we have utilized MRS to better understand chemical changes associated with neurological disorders and treatment response. We have investigated neurometabolic imbalances in brain regions related to post-traumatic stress disorder (PTSD) symptoms and found that neurometabolic changes are brain region-specific in PTSD population compared to healthy controls. MRS was applied to better understand the neurobiological processes of hyperbaric oxygen therapy in military veterans with clinically diagnosed traumatic brain injury and/or PTSD. From preliminary data, we found the largest neurometabolic changes in the insula - a core component of body awareness. Lastly, MRS was utilized to understand neurochemical changes during and following transcranial Direct Current Stimulation (tDCS) for modulation of brain activity in a large healthy cohort. Increases in primary inhibitory neurotransmitter GABA, energy marker creatine, and excitatory neurotransmitter Glx were observed. With improved specificity and the ability to probe microstructural and chemical changes, MRS represents a powerful tool for investigating various disorders and treatment responses.