Encoding and retrieval related cerebral activation in continuous verbal recognition

The differential neuronal activation related to encoding of novel and recog nition of previously studied items and the effect of retrieval effort on ne uronal activation were assessed in a event-related functional magnetic reso nance imaging experiment. A verbal continuous recognition task with two rep etitions of the target items was used. The interpretation of the results wa s focused on brain areas that have been previously reported to be involved in explicit memory. Encoding of novel words in comparison with the first re petition was associated with a stronger activation in the left parahippocam pal and inferior frontal gyrus. Encoding of novel words compared to the sec ond repetition was related to a greater bifrontal activation. Recognition o f studied items was associated with greater activation in the medial and bi lateral inferior parietal lobe at first repetition and in the medial and le ft inferior parietal lobe at second repetition in comparison with encoding of the novel items. Recognition at first repetition compared to recognition at second repetition was associated with greater bilateral frontal activat ion. The results are discussed in relation to current concepts of spatial d ifferentiation of memory function and findings from event-related potential s studies of continuous recognition. (C) 2001 Elsevier Science BY All right s reserved.