Topographical distribution of the auditory N400 component during lexical decision and recognition memory tasks

Abstract

The N400 component of the ERPs is associated with lexical processing and is elicited during both lexical decision (indirect memory) and recognition memory (direct memory) paradigms. To clarify the topographical characteristics of the N400 component, we measured the N400 during memory paradigms in normal subjects. For the lexical decision task, the N400 was maximal at Fz and Cz in young subjects, while in the elderly subjects, the N400 amplitude in the Fz site was smaller than those in the Cz and Pz sites. No significant differences between the right and left sides were found. For the recognition memory task, N400 was maximal at Fz and Cz in both groups and the amplitudes in the left side were larger than those in the right side in both groups. In conclusion, there are some differences in the topographical distribution of the N400 component between the lexical decision and the recognition memory tasks. This suggests that the N400 may be modified by task differences and response style.