Judging semantic and episodic incongruity: a magnetoencephalographic study

Evoked magnetic fields over the entire head were measured during a semantic judgment task, in which conditions of the pre-test learning session were m anipulated. Subjects learnt related and unrelated category-noun pairs, and were then asked to judge the relationship between category and noun. Unrela ted pairs evoked activation around 400 ms in the left temporal area. In add ition, newly presented related pairs, of which the categories were used to learn unrelated pairs, also evoked similar activities. Our findings suggest that these activities are not only related to the semantic incongruity bet ween a pair of words as in previous studies, but also to the episodic incon gruity between the learning and measurement sessions. NeuroReport 12: 195-1 99 (C) 2001 Lippincott Williams & Wilkins.