Entorhinal cortex disruption causes memory deficit in early Alzheimer's disease as shown by PET.

Voxel-based mapping of the correlations between cognitive scores and resting-state brain glucose utilization measured by PET has recently emerged as a novel way to reveal in living patients with Alzheimer's disease (AD) the neural systems whose disruption underlies particular neuropsychological, especially mnemonic, deficits. We have now applied this approach using a novel cognitive paradigm designed to selectively assess verbal episodic memory, and show that in early AD disruption of the left entorhinal cortex underlies this memory deficit, consistent with post mortem data showing that this brain area is affected earliest and most severely by tau pathology in AD.