- Event-related Brain Potentials (ERPs) : Event-related Brain Potentials (ERPs ) is defined as a measure of brain activity. Electrodes placed on the scalp record voltage fluctuations in the brain as the individual perceives or responds to presented stimuli. These voltage fluctuations are electrical potentials associated with the experimentercontrolled events, and the location of the potentials is taken as evidence of where in the brain the processing of that event occurred.