This research study will look at how medications affect the pattern of blood flow in the brain. This study will use a special type of MRI (magnetic resonance imaging) scan called perfusion MRI to make measurements of cerebral (brain) blood flow. The medications we will use in this study are scopolamine (commonly used to treat motion sickness), mecamylamine (used to treat high blood pressure), and donepezil (used to treat memory loss). Cognitive testing will also be obtained, and correlated with the blood flow patterns in the brain.
Project Summary: This research project will investigate the value of combined pharmacologic manipulation and arterial spin-labeled perfusion MRI (pharmacologic ASL-pMRI) as an in vivo probe of cholinergic function. Methods to investigate cholinergic function in vivo are needed to better understand the role of acetylcholine in the physiology of the cerebral cortex, and in cognitive processes in health and in disease states. In this study, pharmacologic ASL-pMRI will be used to characterize the normal cerebral perfusion response to cholinergic manipulation in young healthy subjects. Cognitive measures will also be obtained and correlated with cerebral perfusion changes. Pharmacologic ASL-pMRI and cognitive testing will then be used to study how the cholinergic response is altered with normal aging and in delirium
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Masking
DOUBLE
Enrollment
60
Scopolamine 0.4mg IM x 1 dose; adjustment in older group for weight (0.4mg/70kg)
IM or PO placebo
donepezil 5mg PO x 1
Cerebral blood flow
cerebral blood flow will be measured 3 hours after drug administration using Arterial spin-labeled perfusion MRI
Time frame: 3 hours
cognitive performance
participants will undergo cognitive testing following drug administration and MRI acquisition
Time frame: 4 hours
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