Cognitive task | Findings in Alzheimer's disease | Findings in MCI |
---|---|---|
Episodic memory encoding | ↓ activation in MTL | ↓ adaptive attenuation of hippocampus activation with repeated exposure |
 | ↑ activatio n in right DLPFC, left VLPFC, left OFC, superior temporal gyri, fusiform gyri, and left thalamus | ↓ activation in MTL structures and in bilateral frontal regions in well-characterized amnestic MCI |
 | ↓ activation cingulate, right mPFC, right insula, right superior parietal lobule, and left precuneus | Delayed BOLD response |
 |  | ↑ MTL activation in early MCI patients who had comparable task performance with controls, extent of MTL activity positively correlated with successful encoding |
 |  | Greater MTL functional MRI activation at baseline predicted conversion to Alzheimer's disease |
 |  | ↑ activation in posterior hippocampus and parahippocampal and fusiform regions, together with atrophy of more anterior MTL |
Episodic memory retrieval | ↓ activation in MTL | ↑ activity in PCC |
 | ↑ activation in right DLPFC and left VLPFC, left supramarginal, and left precuneus, and right thalamus | ↓ activity in bilateral frontal regions and left hippocampus |
 | ↓ activation in left claustrum/amygdala, and bilateral insula |  |