event-related brain potential

n. (ERP) Neurons produce extremely small changes in their surrounding electrical fields as they are activated. When many neurons act in synchrony, their electrical fields combine to produce positive or negative changes in the electrical field. Event-related brain potentials (ERPs) represent changes in these electrical fields recorded at the scalp in response to specific events. ERP waveforms are described in terms of the latency (time from stimulus onset) and polarity (positive or negative) of peaks in the waveform, called components. For example, if a list of words is visually presented for a person to remember, a negative peak 100 ms after each word (N100) and a positive peak 300 ms after each word (P300) are produced. Early components (typically less than 200 ms) reflect automatic responses to stimuli, such as detection of a visually presented word. Later components (typically 200 ms or later) reflect higher-order processes, such as trying to remember words.

-GER, FD