Electroencephalography (EEG) based event-related potentials are time-locked to an action. The wave form elicited from a sensory stimulation is comprised of different components depending on the sensory input and the location site that the ERP is associated with. A few components are described below.
The N1 is a negative directed component that occurs approximately 100ms after the stimulus is presented. The N1 caputures processing associated with attention.
The P3 component is a positive directed element that is associated with novely detection in recognition and discrimination tasks. The P3 occurs 300ms after onset of a stimulus.
The N400 is related to processing related to semantic and grammatical processing and is a negative directed component that occurs 400ms after the onset of the stimulus.