Neural correlates of recognition memory with and without recollection in patients with Alzheimer's disease and healthy controls.

To dissociate recognition memory with and without recollection, event-related potentials (ERPs) of patients with Alzheimer's disease (AD) and matched controls were recorded in a test of verbal recognition memory accompanied by a source judgement. AD patients who had smaller hippocampi showed a disability to recollect the study context (source). Their ERPs elicited by correctly recognized old words compared to new items were more positive only between 300 and 500 ms with a maximum over the frontal scalp. Controls exhibited a sustained old/new effect over left temporoparietal and frontal sites. The present findings suggest that preserved recognition memory in patients with mild AD is independent of hippocampally mediated processes recollecting episodic memories.