Learn More
To explore the role of monoamines on cerebral function during specific prefrontal cognitive activation, we conducted a double-blind placebo-controlled crossover study of the effects of 0.25 mg/kg oral dextroamphetamine on regional cerebral blood flow (rCBF) as determined by 133Xe dynamic single-photon emission-computed tomography (SPECT) during performance(More)
We studied regional cerebral blood flow (rCBF) by xenon-133 dynamic single photon emission computed tomography (SPECT) in 17 normal volunteers who were performing the Wisconsin Card Sorting Test (WCST), a task that is particularly sensitive to disturbance of the prefrontal cortex, and a simple matching-to-sample task (BAR) as a sensorimotor control. Three(More)
To address prior reports that schizophrenia is associated with loss of normal brain asymmetry and that it might be linked to a defect of a gene controlling cerebral lateralization, we measured on three-dimensional cortical renderings from magnetic resonance imaging (MRI) scans the lengths and angles of the sylvian fissures in 10 normal monozygotic (MZ) twin(More)
Dynamic physiological scanning, based on temporary changes in local field homogeneity during the passage of a contrast agent bolus, has been performed hitherto with echo-planar imaging (EPI) or conventional gradient-recalled techniques (FLASH). Here, it is shown that the T2* sensitivity of conventional FLASH techniques can be improved drastically on a(More)
This study was performed to measure changes in cerebral blood volume (CBV) associated with visual activation by use of bolus administration of contrast agent and conventional, clinically configured magnetic resonance (MR) hardware and software. Fast gradient-recalled acquisition in the steady state technique was used to study five healthy subjects during(More)
The effects of the alpha-agonists clonidine and guanfacine on rat cortical norepinephrine turnover during morphine withdrawal were assessed. Cortical norepinephrine levels were measured, after administration of alpha-methyl-p-tyrosine, by fluorometric assay. Chronic treatment with morphine did not affect norepinephrine levels or norepinephrine turnover. In(More)
The effects of kainic acid lesions and chronic haloperidol treatment on rat striatal dopaminergic presynaptic receptors were studied. Following the gamma-butyrolactone-induced inhibition of dopaminergic impulse flow, and after dopa decarboxylase inhibition, dopa accumulation and its reversal by dopamine agonists was measured in vivo. 3H-apomorphine (a(More)