EVENT-RELATED POTENTIALS AND RECOGNITION MEMORY - THE EFFECTS OF WORDIMAGERY VALUE

Event-related potentials (ERPs) were recorded from 11 subjects during a recognition memory task. Subjects were auditorily presented with 160 target words and, after about 10 min, they were engaged in a recognit ion task. Subjects were required to determine on each of 320 trials if the word was 'new' (never before presented) or 'old' (heard previousl y). In the recognition test, 160 target words and 160 non-target words were used as stimuli. To assess the effect of word imagery value, 160 stimuli (80 target and 80 non-target) were high imagery words (HI) an d the remaining 160 stimuli were low imagery words (LI). Word frequenc y was balanced across target and non-target words. Results showed that the old/new effect was reflected by a negative component (belonging t o the N400 family, Cz maximum) which was larger for new words in the 4 00-700 ms range. The imagery effect was also present in the 250-550 ms range of the N400, which was larger for HI stimuli. The imagery effec t was present at 400-550 ms only for target words. These results confi rmed the hypothesis that negative components as N400, could reflect pr ocesses occurring during the memory retrieval of items.