Item memory, source memory, and the medial temporal lobe: concordant findings from fMRI and memory-impaired patients

We studied item and source memory with fMRI in healthy volunteers and carried out a parallel study in memory-impaired patients. In experiment 1, volunteers studied a list of words in the scanner and later took an item memory test and a source memory test. Brain activity in the hippocampal region, perirhinal cortex, and parahippocampal cortex was associated with words that would later be remembered (item memory). The activity in these regions that predicted subsequent success at item memory predicted subsequent source memory to a similar degree. In experiment 2, memory-impaired patients with damage thought to be limited to the hippocampal region were given an item memory test and a source memory test, as in experiment 1. The patients were similarly impaired on the item memory test and the source memory test. Together, the findings suggest that medial temporal lobe structures broadly support recognition memory function and that item memory and source memory similarly depend on these structures.