Functional magnetic resonance imaging of cholinergic modulation in mild cognitive impairment

Purpose of review Mild cognitive impairment often represents the earliest clinical phase of Alzheimer's disease and is thought to involve synaptic dysfunction. Functional neuroimaging methods may I be sensitive to these early physiologic changes and may be useful in early detection, therapeutic monitoring, and prediction of treatment response and other clinical outcomes. This review will focus on functional magnetic resonance imaging and its use in measuring the effects of cholinergic modulation in mild cognitive impairment. Recent findings Functional magnetic resonance imaging has begun to be applied to measure changes in regional brain activation during cognitive task performance after pharmacologic manipulation. In mild cognitive impairment, recent reports have appeared demonstrating alterations in neocortical activation after acute and prolonged administration of acetylcholinesterase inhibitors. These functional changes may relate to both behavioral performance and measures of brain structure (e.g., hippocampal volume). Summary Pharmacologic functional magnetic resonance imaging is a rapidly emerging field, with applications in both basic human neuroscience and clinical psychiatry and neurology. Its use in mild cognitive impairment and Alzheimer's disease may provide novel insights into the cholinergic system, memory, and neurodegenerative disease.