Final answer:
EEG activity is commonly recorded from the scalp of human patients, providing valuable data on brain function through the measurement of brainwaves such as frequency and amplitude.
Step-by-step explanation:
In electroencephalography (EEG), the activity is commonly recorded from the scalp of human patients. An array of electrodes is placed around the person's head, which captures the electrical activity emanating from the brain. The printout from these recordings shows the brainwaves, including their frequency and amplitude, providing important information about brain function. EEGs are commonly used for sleep studies and researching various neurological conditions. In contrast, the electrical activity of the heart is measured using an electrocardiogram (ECG), which involves careful placement of electrodes on the skin to record the heart's complex electrical signals.