Various mental operations are involved in responding to a target stimulus. For example, the subject must focus attention on the relevant sensory channel, ignore irrelevant stimuli, distinguish among similar stimuli, and then recognize the target stimulus by matching it to a template stored in the memory. These operations are correlated with electrical activity in groups of nerve cells from the sense organs themselves (i.e., eyes, ears) to the highest centers of information processing in the brain. Researchers have identified certain ERP components that appear to reflect these operations. ERP components between experimental and control subjects are compared in terms of changes in latency and differences in wave height (i.e., amplitude).
