What does an electroencephalogram (EEG) record?

An electroencephalogram (EEG) records brain activity through the measurement of electrical impulses produced by neuron activity. It captures brain waves, which are essentially the electrical patterns that occur as neurons communicate with each other. The EEG device uses electrodes placed on the scalp to amplify these signals, allowing for a detailed analysis of the brain's electrical activity. This physiological data is crucial for diagnosing various neurological conditions, assessing sleep disorders, and monitoring brain function during surgeries.

While a visual display of brain activity is related to EEG, it does not accurately describe the nature of what an EEG records itself. Similarly, computer-generated images of soft tissue refer to imaging techniques such as MRI or CT scans, which are quite different from EEG. Lastly, although brain blood flow and activity can be studied through other imaging techniques such as functional MRI (fMRI) or PET scans, they do not relate to the electrical recording aspect that an EEG focuses on. Thus, the most accurate choice that encapsulates the core function of an EEG is the recording of amplified brain waves.