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1. Individual neurons were recorded extracellularly in the precentral forelimb area of two monkeys trained to perform rapid, large amplitude flexion and extension movements of the contralateral forearm in response to auditory signals. Electromyographic (EMG) activity in the biceps/triceps muscles was recorded separately under the same conditions. The(More)
Using MRI and PET, we investigated the consequences of manganese intoxication in a primate model of parkinsonism and dystonia. Three rhesus monkeys were injected intravenously with doses of 10 to 14 mg/kg of MnCl2 on seven occasions, each a week apart. Two animals became hypoactive with abnormal extended posturing in the hind limbs. These motor disturbances(More)
This report describes the presence of reactive microglia, the accumulation of extracellular melanin, and the extensive loss of dopaminergic neurons in the substantia nigra of monkeys administered 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) 5 to 14 years before death. This evidence of chronic neuroinflammation years after MPTP exposure is similar to(More)
Presynaptic dopamine metabolism was studied in a group of patients with schizophrenia and in an age- and gender-matched normal control group using 6-[(18)F]fluoro-L-DOPA ((18)F-DOPA) and positron emission tomography (PET). Nineteen patients, nine drug-free, 10 on neuroleptics, and 13 normal control subjects underwent PET scans using (18)F-DOPA. The(More)
The effectiveness of 6-[18F]fluoro-L-m-tyrosine (6FMT) to evaluate dopamine presynaptic integrity was compared to that of 6-[18F]fluoro-L-dopa (6FDOPA) in vivo by positron emission tomography (PET). Six normal and six 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-lesioned monkeys received 6FDOPA and 6FMT PET scans on separate occasions with identical(More)
Movement parameters and electromyographic (EMG) studies were carried out in two macaque monkeys performing a rapid arm movement before and after administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Hypokinesia and rigidity were seen after repeated doses. Disturbances in both movements and EMG activity were similar to those reported in(More)
UNLABELLED The reproducibility of (+/-)-alpha-[11C] dihydrotetrabenazine (DTBZ) measures in PET was studied in 10 healthy human subjects, aged 22-76 y. METHODS The scan-to-scan variation of several measures used in PET data analysis was determined, including the radioactivity ratio (target-to-reference), plasma-input Logan total distribution volume (DV),(More)
Arachidonic acid (AA) is an important second messenger involved in signal transduction mediated by phospholipase A2. The goal of this study was to establish an in vivo quantitative method to examine the role of AA in this signaling process in the human brain. A simple irreversible uptake model was derived from rat studies and modified for positron emission(More)
Positron emission tomography was performed on 12 Alzheimer's patients and 12 age-matched normal controls following the administration of the opiate receptor antagonist 6-deoxy-6-beta-[18F]fluoronaltrexone (cyclofoxy, CF). Tracer kinetic analysis was used to determine the volume of distribution of CF, a measure of unoccupied mu and kappa receptor density,(More)