Biofeedback may assist improve physiological functioning or unpleasant discomfort and bodily arousal by telling a person to change what they are doing in the moment, whereas neurofeedback is frequently used to treat types of psychopathology or mental disease and for performance enhancement. However, both techniques have similar goals of helping people become more aware of and control their own brains and bodies. Biofeedback uses instruments such as electroencephalograms (EEGs), electromyographs (EMGs), and galvanic skin response devices to show a user information about their brain waves or other physical processes. This information is then used to help them modify their behavior in order to affect the physiology that they are observing. For example, an individual with epilepsy can use this information from an EEG to know when a seizure is coming on. They can then take measures such as getting out of bed or going into a secluded area to prevent having a seizure. Neurofeedback uses instruments such as functional magnetic resonance imaging (fMRI) and positron emission tomography (PET) to measure changes in blood flow and neural activity in specific parts of the brain. These measurements are displayed on a computer screen and used by researchers to identify changes in the brain's activity pattern during certain tasks or under specific conditions. Neurofeedback works by having the patient learn to control these changes by adjusting their thoughts and actions.