The cholinergic system in mild cognitive impairment and Alzheimer's disease: Providing a rationale for nicotinic receptor PET?

The cholinergic system in mild cognitive impairment and Alzheimer's disease: Providing a rationale for nicotinic receptor PET? The cholinergic system has long been linked to cognitive processes. Degeneration of the cholinergic system as seen in dementia of Alzheimer's type correlates with cognitive decline. In the last few years, brain imaging with positron emission tomography (PET) using cholinergic receptor ligands has been utilised as a tool to investigate changes in the cholinergic system in patients suffering from Alzheimer's disease (AD) in vivo. Here, we provide an overview of previous findings on the relationship between cholinergic manipulation, especially of the nicotinic receptor system, and cognition in Alzheimer's disease and amnestic mild cognitive impairment (MCI) in order to evaluate the theoretical basis for the use of nicotinic receptor PET as a diagnostic tool in those disorders.