Superior temporal gyrus and planum temporale in schizophrenia: A selective review

1. 1. The normal structure of the superior temporal gyrus (STG) has been elucidated from human and non-human primate research. This brain region is structurally complex, contains several distinct cellular regions and the area known as the planum temporale.

2. 2. The STG connects with heteromodal neocortical regions and temporolimbic areas.

3. 3. Functional studies of the normal STG in animals and in humans, using electrophysiology and PET/ fMRI, emphasize the STG's role as part of a cortical network important in the interpretation, production and self-monitoring of language.

4. 4. There is evidence for structural abnormalities of the STG in schizophrenia including both volume reductions and disturbances of normal asymmetries.

5. 5. Functional studies of this region in schizophrenic patients, including measurements of evoked potentials and of bloodflow, are abnormal, especially when patients perform language tasks or experience hallucinations.

6. 6. This structural and functional pathology in the STG probably represents one example of a more general disruption in schizophrenia of the neocortical network of which this region is an essential part. This disturbance may be closely associated with the symptoms of formal thought disorder and of auditory hallucinations commonly seen in the disorder.

     

Echographic Detection of Latent Severe Thrombotic Stenosis of the Superior Vena Cava and Innominate Vein in Patients with a Pacemaker: Integrated Diagnosis Using Sonography, Pulse Doppler, and Color Flow

Thrombosis of the innominate vein and SVC is a serious complication in patients with pacemakers, inducing puhnonary embolism or SVC syndrome. Venography is the definitive method for its diagnosis; however, it is too invasive for related studies. The purpose of this study was to validate sonography, pulse Doppler, and color flow in detecting noninvasively innominate vein or SVC thrombosis in patients with pacemakers. In 53 patients with pacemakers, the 1 severe SVC stenosis and 18 severe innominate vein stenoses due to thrombosis were diagnosed by digital subtraction angiography. Sonography accurately showed the severe SVC stenosis due to thrombosis, but had limitations on the innominate vein thrombosis. Color flow demonstrated mosaic flow, indicating poststenotic turbulence due to stenosis of the innominate vein and SVC caused by thrombosis in 15 of 16 patients, and pulse Doppler disclosed absence of flow due to complete occlusion of the innominate vein in 2 of 2 patients. Sensitivity and specificity for detecting severe innominate vein stenosis due to thrombosis using combined color flow and pulse Doppler was 94% and 100%, respectively. In conclusion, sonography, pulse Doppler, and color flow allow accurate detection of severe innominate vein or SVC stenosis due to thrombosis, and are therefore useful for the follow-up of patients with a pacemaker.     

Glutamate‐induced Co2+ uptake in rat auditory brainstem neurons reveals developmental changes in Ca2+ permeability of glutamate receptors

Ca²⁺ influx through glutamate receptors (GluRs) is thought to play a crucial part in developmental processes and neuronal plasticity. Here we have examined the spatiotemporal distribution of Ca²⁺-permeable GluRs in auditory brainstem neurons of the rat from birth to adulthood, using the cobalt-staining technique of Pruss and collaborators. In slices of young adult rats, 1 mm glutamate evoked intense cobalt uptake in subsets of neurons in the ventral cochlear nuclei, the medial nucleus of the trapezoid body, the lateral and the medial superior olive, and the lateral lemniscal nuclei. Neurones in the central nucleus of the inferior colliculus, and thalamic auditory nuclei appear to express few, if any, Ca²⁺-permeable GluRs. Thus, in adults, Ca²⁺-permeable GluRs are present in neurons of almost all main relay stations of the auditory brainstem. During development, cobalt-stained cells first appeared at about hearing onset (at postnatal day 12 [P12]). At P16, staining levels were highest and the pattern of distribution was already adult-like. The staining intensity slightly declined during the fourth postnatal week. In contrast, Ca²⁺-permeable receptors were detected in the external cortex of the inferior colliculus as early as P4. Our results show that auditory neurons, characterized by a high temporal precision in neuronal activity, display Ca²⁺-permeable GluRs. Because Ca²⁺ permeability appears at about the onset of hearing and is highest during the following 2 weeks, Ca²⁺ influx through GluRs is likely to be implicated in remodelling processes occurring during this ontogenetic period.     

Somatosensory evoked potentials are not a sensitive indicator of potential positioning injury in the prone patient

Objective. This study monitored somatosensory evoked potentials (SSEP) at the median and ulnar nerves in awake volunteers placed in a simulated position for prone surgery. Neurologic symptoms were used as a surrogate end-point for position related peripheral nerve injury; the occurrence of these symptoms was correlated with the presence or absence of SSEP changes in median and ulnar nerves.Methods. Median and ulnar nerve SSEP data was obtained from awake volunteers in the supine and prone positions. With the head midline in the prone position, SSEPs were measured as the arms were advanced in four cephalad increments. Symptoms, defined as tingling, numbness, or aching in the hand, forearm, or upper arm, were recorded at each position. SSEP changes were considered significant when amplitude decreased 60% and/or latency increased 10% compared with baseline prone measurements. Symptoms were correlated with SSEP changes using chi-squared analysis (p < 0.05), and Fisher's exact analysis (p < 0.07).Results. Data were collected on 14 patients, mean age 34 ± 3 years. Seven (50%) subjects reported symptoms with changes in position, while four (29%) subjects displayed SSEP changes. There was no statistically significant association between symptoms and SSEP changes. There were no false positives (no symptoms in the presence of significant SSEP changes), but there were 3 (21%) false negatives (positive symptoms without SSEP changes).Conclusions. While all SSEP changes were associated with symptoms, the development of symptoms in 3 of 7 patients without SSEP changes suggests that SSEPs may be an imperfect monitor for the detection of positioning injury. The limited sensitivity of SSEPs in this study may be due to the duration of the monitoring, sample size, or the validity of symptoms as a surrogate for nerve injury.     

Multiple aneurysms of the visceral arteries with migrating vascular bruit on postural change: A case report

Multiple aneurysms of the gastroepiploic artery and the ileocecal branch of the superior mesenteric artery were found in a 68-year-old male patient by angiography. The patient presented with one-hour postprandial epigastric pain of 10 years duration. Abdominal bruit was auscultated at the two different sites, one of which shifted downwards upon upright position. From the freely movable nature of the great omentum, this bruit, migrating upon postural change, was most likely from the gastroepiploic artery aneurysms. The aneurysms were excised and the abdominal bruit disappeared. The etiology of the aneurysms was suggested to be arterial fibrodysplasia histologically. From this experience, it was stressed that postural change should be added to a routine physical examination to rule out an aneurysm from the freely movable great omentum.     

Modulation of esophageal peristalsis by alterations of body position

Previous studies have demonstrated that nonviscous liquids traverse the esophagus more rapidly with the subject in the upright rather than the supine position. Conversely, similar studies have shown that viscous liquids traverse the esophagus at similar rates for both upright and supine positions. Our purpose was to define the motor correlates of these differing responses. Six normal volunteers were studied with an infused catheter system incorpoating a Dent sleeve for monitoring lower esophageal sphincter pressure. The subjects were given a series of swallows of a water and a viscous (52 centipoise) bolus in both the supine and upright positions. In the upright position, the water bolus caused an increased velocity of propagation in the proximal esophageal segment that was associated with a shortening of lower esophageal sphincter relaxation time and reductions in amplitude and duration of contraction. No significant changes in the peristaltic wave were noted with the viscous bolus during alterations of body position. We conclude that the more rapid transit of a nonviscous water bolus through the esophagus in the upright position is reflected in specific alterations of esophageal peristaltic parameters. The possible mechanisms for these differing responses are discussed.     

Opposing effects of vasopressin on matching versus non-matching to position: further evidence for response,not memory,modulation

Rats were trained on either of two related variants of an operant memory task. In the matching to position (MTP) task, one of two retractable response levers appeared, at random, as the sample. A response caused the lever to retract and this was followed by a delay (0–32 s) interval, during which the subjects had to approach and respond at the magazine tray. Both levers were then presented and the rat had to respond, for food reward, to the one which had appeared as the sample. A second group of rats learned non-matching to position (NMTP). This task was very similar to MTP, with one crucial difference: here, the subject had to respond to the lever which hadnot appeared as the sample. Both groups of rats learned their respective tasks rapidly, performance depending on the delay interval as expected. They were then injected, peripherally, with different doses of arginine-vasopressin (AVP: 0–25 µg/kg), a peptide which others have argued improves mnemonic performance. There was evidence to suggest that MTP performance was improved by AVP; on the other hand, NMTP performance appeared to be disrupted. It is suggested that AVP induces a bias towards responding on one side of the two lever test chamber. In other words, it affects motor or motivational, not mnemonic mechanisms.     

不典型胆脂瘤36例X线分析

本文对36例胆脂瘤患者的X 线片作了回顾性分析,提出在Mayer's 位片上的测量方法。测得患侧上鼓室横径平均值为5.9mm,最大值8.2mm.最小值4.0mm;正常侧平均值为3.9mm,最大值6.7mm.最小值3.0mm。患侧鼓窦入口最小径平均值为4.1mm,最大值6.0mm,最小值2.5mm;正常侧最小径平均值为2.4mm,最大值3.5mm.最小值1.0mm。结果显示上鼓室横径>5.0mm和/或鼓窦入口最小径≥3.0mm 者提示不典型胆脂瘤诊断。     

Transient subcortical connections of inferior temporal areas TE and TEO in infant macaque monkeys

Whereas in mammals postnatal neurogenesis, gliogenesis, and angiogenesis appear to be kept at low rates, in fish the capability for the production of new brain cells during adulthood is very pronounced. Many of the newly generated cells originate from germinal layers that maintain their proliferative activity during adulthood. By employing incorporation of the thymidine analogue 5-bromo-2′-deoxyuridine (BrdU) into mitotic active cells, we have quantitatively mapped such proliferation zones in the brain of adult Apteronotus leptorhynchus (Gymnotiformes, Teleostei). In the telencephalon, diencephalon, mesencephalon, and rhombencephalon, the total number of BrdU-labelled cells was low, making up approximately 25% of all mitotic active cells in the brain. Many of these cells were scattered over wide areas. Otherwise, zones of high proliferative activity were typically located at or near the surface of ventricular, paraventricular, and cisternal systems. Approximately 75% of all BrdU-labelled cells found in the brain of adult Apteronotus leptorhynchus were situated in the cerebellum. Zones displaying proliferative activity were restricted to small areas, such as narrow stripes around the midline of corpus cerebelli and valvula cerebelli, the boundary between corpus and valvula, and a large portion of the area covered by the eminentia granularis medialis. Counts indicate that, on average, 100,000 cells, corresponding to approximately 0.2% of the total population of cells in the brain of adult Apteronotus leptorhynchus, are in S-phase within a period of 2 hours. At least part of these newly generated cells is added to the population of already existing cells. This leads to a permanent growth of the brain with increasing size of the fish, a process that appears to slow down only in individuals of relatively advanced age. © 1995 Wiley-Liss, Inc.     

Lesions of the superior colliculus in the rat differentiate between nigrostriatal and mesolimbic dopamine systems

Bilateral electrolytic lesions of the superior colliculus in rats increased spontaneous locomotor activity, enhanced amphetamine-induced hyperactivity and attenuated apomorphine-induced biting. These lesions were associated with an increased rate of turnover of dopamine in the nucleus accumbens, but not in the striatum. Similarly concentrations of the dopamine metabolites homovanillic acid and 3,4-dihydroxyphenylacetic acid were elevated in accumbens tissue but not in striatum in rats with bilateral collicular lesions. The results indicate that lesions of the superior colliculus cause differentiation between hyperactivity and stereotypy, and that this may be related to blockade of a nigrostriatal outflow, and relief of inhibition on mesolimbic systems.