Another way to obtain an N400 is by means of semantic priming of single words. A word is responded to more quickly and accurately if it is preceded by the same or related words (primed) than if it follows unrelated words. In the example “table—chair,” “chair” is said to be primed by “table.” Semantic priming can be measured either with reaction time or the N400 ERP. In normal subjects, unprimed words elicit larger N400’s than primed words; primed words elicit small or absent N400’s.
