Stress arises when external demands exceed personal resources, disrupting internal balance. While moderate stress can enhance performance depending on type, timing, and duration, chronic or excessive stress may impair cognitive, emotional, and neurological functioning. My research explores the brain mechanisms underlying these effects, focusing on structural (white matter) and functional changes related to emotion regulation and memory, particularly in individuals under stress or with trauma exposure. Using behavioral tasks from cognitive psychology, I assess performance (e.g., reaction time, accuracy) alongside neuroimaging techniques (MRI, EEG, fMRI) to correlate brain changes with clinical outcomes. During my PhD, I identified potential imaging biomarkers for early detection of stress-related disorders. My current work validates these markers, especially white-matter alterations, as predictors of stress vulnerability. Studies in youth at risk for depression support this, showing white-matter abnormalities. These findings advance understanding of the structural and functional basis of anxiety sensitivity and PTSD, helping improve diagnosis, treatment, and risk assessment. Additionally, I investigate how changes in brain connectivity affect cognition in individuals with traumatic brain injury (TBI) or mild cognitive impairment (MCI), with the goal of informing better mental health interventions.