An event-related potential (ERP) is any stereotyped electrophysiological response to an internal or external stimulus. In simple terms it is any measured brain response that is the direct result of a thought process or perception.
ERPs can be reliably measured using electroencephalography (EEG). This method utilizes surface electrodes to measure the electrical activity of the brain (specifically the cortex) through the skull and scalp. As the EEG reflects many thousands of simultaneously ongoing neuronal processes, the brain’s response to a specific stimulus or event of interest is rarely visible in the ongoing EEG. In actual recording situations, even the most robust ERPs emerge only after many dozens of individual presentations of the stimulus of interest are averaged together. This technique cancels out noise and spontaneous EEG and enhances the voltage response to the stimulus making it stand out clearly from the averaged out background.
While evoked potentials may reflect the processing of the physical stimulus, they may also be modulated or even mediated by the „higher“ processes involving memory, expectation, attention, or changes in mental state.
Experimental psychologists and other neuroscientists have revealed many different stimuli and paradigms to elicit reliable ERPs from their subjects. The timing of these responses is thought to represent timing of the brain‘s communication during information processing.
As ERPs are temporally locked to stimuli, therefore EEG amplifiers need to be equipped with trigger inputs capable of registering markers related to stimulus events occurring during continuous and ERP like EEG acquisitions. All Brain Products amplifiers are capable of recording such events and therefore can record evoked potentials. Simple online averaging options as well as sophisticated offline data processing are just basic examples of the huge menu of functions our software offers for ERP and wider EEG analysis.