To investigate the neural correlates of episodic recollection the ERP corre
lates of memory for new associations (recently studied novel word pairs) we
re investigated using two tasks, associative recognition and associative re
call. For the recognition task subjects discriminated old from new word pai
rs and, for pairs judged old, reported whether the pairs were intact or rec
ombined (compared to at study). For the recall task, subjects discriminated
old from new words and, for each word judged old, reported its study assoc
iate. ERPs were recorded at test from 25 scalp electrodes, with a 1944-ms r
ecording epoch. In Experiment 1, the tasks were randomly interleaved. Consi
stent with previous findings, relative to the ERPs for correctly classified
new items, the ERP correlates of successful associative recognition consis
ted of a sustained left parietal positivity, and two frontal positivities,
one early and bilateral, the other occurring later and showing a right-side
d maximum. In contrast to previous findings, successful associative recall
elicited similar effects to those found for recognition. Topographic analys
es revealed that the distribution of these retrieval-related ERP effects we
re similar across the two tasks, suggesting that the recognition and recall
of associative information gives rise to activity in overlapping, if not t
he same, neural populations. In Experiment 2 the tasks were blocked. In con
trast to the findings of Experiment 1, successful associative recall elicit
ed left parietal and late onsetting right frontal positivities, in the abse
nce of the early bilateral frontal positivity. This finding suggests that f
rontally-distributed memory-related ERP effects are both neurally and funct
ionally dissociable. Specifically, we argue that the functional significanc
e of the early frontally distributed ERP effect cannot be accounted for by
the 'post-retrieval processing' hypothesis that is taken to account for the
late right frontal effect, suggesting that episodic recollection itself is
neither neurally nor functionally homogenous. (C) 1999 Published by Elsevi
er Science B.V. All rights reserved.