Final answer:
An Electroencephalography (EEG) is a clinical test used to measure the electrical activity in the brain by using electrodes, whereas a functional magnetic resonance imaging (fMRI) generates a 3D map of the brain's active areas during tasks.
Step-by-step explanation:
The clinical test used to measure the electrical activity in the brain is called an Electroencephalography (EEG). This technique uses an array of electrodes placed around a person's head to record electrical signals. The EEG generates a printout of the brain's electrical activity, or brainwaves, showing both the frequency and amplitude of the recorded waves. This test can provide valuable information within milliseconds and is particularly useful in research areas such as studying sleep patterns in individuals with sleep disorders.
Another technique that measures brain activity is the functional magnetic resonance imaging (fMRI), which differs from the EEG. While the EEG provides information on the overall brain's electrical activity, the fMRI generates a map of the most active brain areas during specific tasks, showing changes in brain tissue associated with those tasks. This method is beneficial for visualizing and understanding brain function in three dimensions.