Ultrasonographic findings of normal and pathologic placenta and umbilical cord

Functional neuroanatomy of visually elicited simple phobic fear: additional data and theoretical analysis

We investigated central nervous system correlates of simple phobic fear. Regional cerebral blood flow (rCBF) was measured using positron emission tomography (PET) in eight volunteers with symptomatic spider phobia that were exposed to visual phobogenic and neutral stimuli. Diazepam (0.1 mg/kg body weight i.v.) or placebo was administered under double-blind conditions after initial PET scans. The PET scans were then repeated. The presence of fear was confirmed by rating procedures and increased number of nonspecific electrodermal fluctuations and by higher heart rate during phobic than during neutral stimulation. Phobic as compared to neutral stimulation elevated the regional to whole brain (relative) CBF in the secondary visual cortex but reduced relative rCBF in the hippocampus, prefrontal, orbitofrontal, temporopolar, and posterior cingulate cortex. Diazepam treatment did not affect the relative rCBF or the subjective or physiological fear indices. The observed rCBF pattern replicates our previous findings in snake phobics (M. Fredrikson et al. [1993] Psychophysiology, 30, 127-131; G. Wik et al. [1993] Psychiatry Research (Neuroimaging), 50, 15-24) and indicates that fear and anxiety affect cortical areas outside the classic limbic system areas.

Somatosensory Discrimination of Shape: Tactile Exploration and Cerebral Activation

This study of somatosensory discrimination of rectangular parallelepipeda with the right hand had three purposes: (i) to describe the exploratory finger movements; (ii) to reveal the anatomical brain structures specifically engaged in the production of exploratory finger movements; and (iii) to reveal the anatomical structures specifically engaged in the discrimination of tactually sensed shape. The thumb was the most active finger, moving with a mean exploration frequency of 2.4 Hz, as evident from videotape records of the exploratory finger movements. The cerebral structures activated during somatosensory discrimination were mapped by measurements of regional cerebral blood flow (rCBF) in six healthy male volunteers with positron emission tomography (PET) and the use of the computerized brain atlas of Greitz et al. (1991, J. Comp. Ass. Tomogr., 15, 26 - 38). The rCBF changes caused by somatosensory discrimination were compared point-to-point to a PET-study on right-hand finger movements and a PET-study on vibration stimulation of the right hand. From these results the following conclusions were drawn. The rCBF increase in the left superior parietal lobule indicated the site engaged in the analysis of shape. The rCBF increases in the left supplementary sensory area, bilaterally in premotor areas, in the left putamen, the right dentate nucleus and bilaterally in the posterior cerebellum were related to the control of the tactile exploratory finger movements. The rCBF increases in the right homologue of Broca's area, bilaterally in the superior prefrontal cortex and in the right midfrontal cortex probably resulted from working memory, the direction of attention, and the discrimination process.

Cortical benzodiazepine receptor binding in patients with generalized and partial epilepsy

Impaired cortical inhibition may be involved in epileptogenic mechanisms. In a positron-emission tomography (PET) study, we demonstrated a reduction of the cortical benzodiazepine (BZD) receptor density in the epileptic foci of patients with partial epileptic seizures. In the present study, we used the same method in 10 patients with primary generalized epilepsy to determine whether an altered BZD receptor binding could also be demonstrated in this patient group. The [11C]-labeled BZD receptor antagonist Ro 15-1788 was used as ligand. Receptor affinities and densities were calculated in various cortical regions and then compared with the values from corresponding "nonepileptic" regions in the previously examined partial epilepsy patients. Focal alterations of the BZD receptor density or affinity were not demonstrated in patients with generalized epilepsy. This patient group had a slight tendency toward lower mean cortical BZD receptor density, however, as compared with corresponding values from 10 patients with partial epilepsy. Our results strongly suggest that a focal alteration of cortical inhibition is not a prominent feature of human generalized epilepsy. The observed tendency toward lower mean cortical BZD receptor density may be a consequence of diffusely impaired cortical inhibition. Further investigations of this issue are therefore indicated.

Distribution of remoxipride to the human brain and central D2-dopamine receptor binding examined in vivo by PET

Remoxipride is a new antipsychotic drug that binds selectively to the D2-dopamine receptor subtype as demonstrated in animal studies in vitro and in vivo. It is generally assumed that the antipsychotic effect of neuroleptic drugs is mediated by blockade of dopamine receptors. The aim of the present study was to use positron emission tomography (PET) and the ligand [11C] raclopride to examine the central D2-dopamine receptor occupancy in man during oral administration of remoxipride. After oral administration of remoxipride 100 mg three times daily to a healthy male subject there was a 73% central D2-dopamine receptor occupancy. In a schizophrenic patient treated with remoxipride 200 mg twice daily there was a 71% occupancy. These occupancy values are similar to the values of 65-85% previously found in a series of patients treated with neuroleptics representative of all currently used chemical classes. In a separate experiment, remoxipride was labelled with 11C and injected intravenously and the distribution of radioactivity to the brain examined. Radioactivity appeared in the brain during the first minutes after injection and 4.5 min after injection it accounted for 0.8% of the total radioactivity injected, thus indicating that [11C]remoxipride had rapidly passed through the blood-brain barrier.

Changes in Regional Cerebral Oxidative Metabolism Induced by Tactile Learning and Recognition in Man

We measured the regional cerebral oxidative metabolism (rCMRO2) with positron emission tomography in normal healthy volunteers in three different stages: rest, tactile learning, and tactile recognition of complicated geometrical objects. The frequency of manipulatory movements during tactile recognition was twice that of tactile learning. Tactile recognition with the right hand increased rCMRO2 in six prefrontal cortical areas, bilaterally in the supplementary motor areas, the premotor areas and supplementary sensory areas, in the left primary motor and primary sensory area, in the left anterior superior parietal lobule, bilaterally in the secondary somatosensory area, the anterior insula, lingual gyri, hippocampus, basal ganglia, anterior parasagittal cerebellum, and lobus posterior cerebelli. These structures have in other studies been found to participate in manipulatory movements and analysis of somatosensory information. Tactile learning increased rCMRO2 in the same structures as did tactile recognition. Thus we found no differences in the anatomical structures participating in storage and retrieval. However the rCMRO2 increases in the left premotor cortex, supplementary motor area, and left somatosensory hand area were larger during tactile recognition in accordance with the higher frequency of manipulatory movements and higher flux of somatosensory information from the periphery during recognition. Despite this the rCMRO2 was significantly higher in the neocerebellar cortex during tactile learning. Since there were no learning effects on the manipulatory movements, this extra metabolic activity in the lateral cerebellum was attributed to energy demanding processes associated with climbing fibre activity during storage of somatosensory information.

PET determination of regional cerebral glucose metabolism in alcohol-dependent men and healthy controls using 11C-glucose

Regional brain glucose metabolism was determined in 9 male alcohol-dependent inpatients and 12 male healthy controls. All the patients were socially impaired by the alcohol abuse. All the subjects had abstained from alcohol and drugs for more than four weeks before entering the study. Brain glucose metabolism was determined by positron emission tomography (PET) with 11C-glucose as the tracer. Regions of interest were drawn on displayed computed tomographic (CT) images of the brain. Regions were transferred to corresponding PET slices, allowing the determination of regional glucose metabolism. In the healthy volunteers there was a reduction in glucose metabolism with age. In 11 of the 19 brain regions examined, the alcoholics had a 20% to 30% lower glucose metabolism than the controls. This was true for both cortical and subcortical structures. The distribution of relative regional metabolic rates indicated that parietal cortical areas were most affected. Atrophic changes as shown by CT were not correlated to the reduced metabolism in the alcohol-dependent patients.

Altered relationships between metabolic rates of glucose in brain regions of schizophrenic patients

Regional brain glucose metabolism was studied with positron emission tomography (PET) in healthy volunteers (n = 9) and schizophrenic patients (n = 15). The patients were in an acute phase of the disease and drug free. Cerebral metabolic rate with 11C-glucose as the tracer (CMRgl) was determined in both cortical and subcortical structures. In the healthy volunteers significant correlations were found between metabolic rates of some regions, but no relationships were found between CMRgl of limbic cortical areas and that of neocortical or subcortical structures. In the patients, high and significant positive correlations were found between metabolic rates in the neocortical areas, the limbic cortical areas and the subcortical areas. The results indicate differences in the neuronal interplay between regions of healthy and schizophrenic subjects. It is proposed that neuronal systems guiding the specificity and diversity in neuronal functions between different brain regions, are abnormal in schizophrenic patients. Such a disturbance may be the basis for the diversity of psychiatric symptoms in schizophrenics.

A prenatal diagnosis of umbilical cord oedema made by ultrasound; a case report

A case of marked oedema of the umbilical cord is described associated with premature onset of labour. The diagnosis was made by ultrasound at 33 weeks gestational age. There were no other malformations of the fetus, cord or placenta.