Which of the following best describes brain imaging?

The correct answer highlights that brain imaging encompasses techniques designed to visualize and capture images of brain activity, providing critical insights into the functioning of the brain. One of the most notable techniques is functional Magnetic Resonance Imaging (fMRI), which detects changes in blood flow and oxygenation levels in the brain, allowing researchers to infer which areas are active during specific tasks or at rest. This imaging capability is crucial for understanding brain processes, diagnosing conditions, and researching cognitive functions and their neural underpinnings.

By contrast, the other options describe different concepts that do not align with the definition of brain imaging. For instance, using direct electrical stimulation to map brain activity is associated with methods such as brain mapping or electrocorticography, which differ fundamentally from the imaging techniques that capture visual representations of brain activity. Meanwhile, psychological tests to assess cognitive function focus on behavior or performance rather than visualizing brain activity itself. Lastly, theoretical concepts related to cognitive processing may inform our understanding of brain function but do not involve the actual imaging of neural activity.