Low density of sigma1 receptors in early Alzheimer's disease.

Objective: The sigma(1) receptor is considered to be involved in cognitive function. A postmortem study reported that the sigma(1) receptors were reduced in the hippocampus in Alzheimer's disease (AD). However, in vivo imaging of sigma(1) receptors in the brain of AD patients has not been reported.

Increased regional cerebral blood flow but normal distribution of GABAA receptor in the visual cortex of subjects with early-onset blindness.

Before the completion of visual development, visual deprivation impairs synaptic elimination in the visual cortex. The purpose of this study was to determine whether the distribution of central benzodiazepine receptor (BZR) is also altered in the visual cortex in subjects with early-onset blindness. Positron emission tomography was carried out with [(15)O]water and [(11)C]flumazenil on six blind subjects and seven sighted controls at rest.