Final answer:
The development of fMRI and PET scans has revolutionized our ability to study brain functions during cognitive processes by providing detailed images of brain activity and functionality.
Step-by-step explanation:
The two brain imaging techniques that have allowed us to study brain functions during cognitive processes are functional magnetic resonance imaging (fMRI) and positron emission tomography (PET) scans. The fMRI is a powerful tool that tracks changes in blood flow and oxygen levels to map brain activity over time, providing detailed images of brain structure and function. PET scans, although not as detailed as fMRI, are useful in examining the brain's anatomy and function, monitoring the brain's use of oxygen and water, and identifying regions concerning metabolic activity related to diseases like Alzheimer's.