Brain imaging has revealed how the brain’s structure and activity support memory, perception and behavior, and how these change in health and disease. Modern techniques differ in what they measure and how precisely they locate and time brain events.

Structural MRI provides detailed images of brain anatomy, allowing researchers to measure the volume and thickness of regions such as the hippocampus and cortex. This has helped track age related atrophy and structural differences in conditions like Alzheimer’s disease, depression and schizophrenia.

Functional MRI (fMRI) measures changes in blood oxygen as an indirect marker of neural activity. It has identified networks for language, vision, attention and memory, and shown how these networks reconfigure during tasks, learning and rest. Resting state fMRI has been used to map intrinsic connectivity patterns that differ across individuals and clinical groups.

Diffusion tensor imaging tracks the diffusion of water along white matter tracts, revealing the integrity and organization of connections between regions. This has been crucial for studying developmental changes, brain plasticity after injury and disconnection in psychiatric and neurodegenerative disorders.

Electroencephalography and magnetoencephalography record electrical and magnetic activity with millisecond precision, capturing fast dynamics during perception and decision making. Although their spatial resolution is lower than MRI, they are powerful for studying brain rhythms and temporal processing.

By combining these methods, researchers link micro level activity and macro scale networks to cognition and behavior. Current work applies brain imaging to early diagnosis, prediction of treatment response, monitoring disease progression and guiding personalized interventions, while emphasizing the need for careful interpretation, replication and integration with other biological and behavioral data.