Anterior hippocampus orchestrates successful encoding and retrieval of non-relational memory: an event-related fMRI study.

Episodic memory encoding and retrieval processes have been linked to different neural networks. However, the common brain regions associated with non-relational memory processing during successful encoding (subsequent memory effect) and successful retrieval (recognition effect) have not yet been investigated. Further, the majority of functional imaging studies have been conducted in young subjects, whereas patients from lesion studies, where most neuropsychological models are still based upon, are usually older.

Hippocampal activation in patients with mild cognitive impairment is necessary for successful memory encoding.

Background: Episodic memory enables us to consciously recollect personally experienced past events. Memory performance is reduced in patients with mild cognitive impairment (MCI), an at-risk condition for Alzheimer's disease (AD).

Patients And Methods: We used functional MRI (fMRI) to compare brain activity during memory encoding in 29 healthy elderly subjects (mean age 67.

Successful verbal retrieval in elderly subjects is related to concurrent hippocampal and posterior cingulate activation.

Objective: Memory decline and hippocampal atrophy are two major aspects of Alzheimer's disease. Using a response-related fMRI design, we investigated the relationship between successful verbal retrieval and concurrent cerebral activation in elderly subjects in different stages of cognitive decline. We chose a correlational over the more traditional categorical approach to increase the power of detecting relevant activations.

Mild cognitive impairment (MCI) and actual retrieval performance affect cerebral activation in the elderly.

Cerebral activation in the elderly may depend on general cognitive decline as well as actual retrieval performance. Consequently, activation between subjects with and without Mild Cognitive Impairment (MCI), and between remembered and non-remembered words was compared. Twenty-one MCI and 29 healthy control subjects learned 180 nouns.

Volume reduction of the entorhinal cortex in subjective memory impairment.

To examine the biological basis of subjective memory impairment (SMI), defined as the feeling of memory worsening with normal memory performance, we measured the volume of the entorhinal cortex (EC) and the hippocampus in SMI subjects, patients with mild cognitive impairment (MCI), patients with Alzheimer's disease (AD) and healthy controls (CO). Compared with controls, the EC was smaller in the SMI group (left: p=0.060; right: p=0.