Functional magnetic resonance imaging (fMRI) activity in the hippocampal region during recognition memory

Neuroimaging studies have often failed to observe activity in the hippocamp al region during memory retrieval. Recently, two functional magnetic resona nce imaging studies reported activity in the hippocampal region associated with recollective success. In both, participants studied pictures of object s and were given a recognition memory test with words that either did or di d not name the studied objects. The recognition test was therefore cross-mo dal or associative in nature. These findings raise the question of what cir cumstances are required to observe activity in the hippocampal region durin g memory retrieval. Here, we report that robust hippocampal activity for ta rgets relative to foils occurred during retrieval in a recognition memory t ask when single words were used at both study and test, as well as when pic tures of single nameable objects were used at both study and test. The hipp ocampal region is involved not just in overtly associative tasks but more b roadly in the recollection of recently occurring facts and events.