Postural dependence of reaction time in normal subjects and patients with focal brain lesions.

EMG reaction times (EMG-RTs) of triceps brachii muscle of normal subjects and patients with focal brain lesions were measured at two different positions of the shoulder joint. The difference of EMG-RTs between the two positions was smaller in patients with VL-thalamotomy, cerebellar or frontal premotor lesions than in normal subjects and patients with hemiplegia. It is assumed that cerebellum, VL-nucleus and the premotor area are related to the proprioceptive control of RTs.     

Perceptual-motor activity in children with focal lesions of the brain]

The pathology of the motor analyser, originating in connection with local lesions of the brain may be studied by means of sensorimotor tracing method. By this parameter, localizations of the lesion produce dissimilar disturbances of the percentive-motor activity. Disorders in movement control were revealed in the case of disturbance of interhemispheric relations resulting from a lesion of the dominant hemisphere; as a result of disfunction of the frontal lobes, which led to disturbance of prognostication; due to disturbance of the "body scheme" and proprioreception disturbances.     

Assessment of recognition of emotions by healthy persons and patients with focal brain pathology

To assess the involvement of different structures of the human brain into successive stages of the recognition of the principal emotions by facial expression, we examined 48 patients with local brain lesions and 18 healthy adult subjects. It was shown that at the first (intuitive) stage of the recognition, premotor areas of the right hemisphere and temporal areas of the left hemisphere are of considerable importance in the recognition of both positive and negative emotions. In this process, the left temporal areas are substantially involved into the recognition of anger, and the right premotor areas predominantly participate in the recognition of fear. In patients with lesions of the right and left brain hemispheres, at the second (conscious) stage of recognition, the critical attitude to the assessment of emotions drops depending on the sign of the detected emotion. We have confirmed the hypothesis about a correlation between the personality features of the recognition of facial expressions and the dominant emotional state of a given subject.     

Characteristics of the perception and imagination of emotions in patients with focal brain pathology

Voluntary components of the emotion perception were shown to be related to the left hemisphere temporal area in patients with focal lesions of postero-frontal and temporal areas of both hemispheres, whereas the involuntary components required involvement of the right hemisphere temporal area. The voluntary components of the emotion reproduction are associated with involvement of the left hemisphere postero-frontal area, whereas involuntary components of perception are related to work of the right hemisphere postero-frontal area. The data obtained suggest that the voluntary (conscious) recognition and reproduction of emotions are mainly related to the sensory and motor speech centres of the left hemisphere, whereas involuntary those involve symmetrical areas of the opposite hemisphere.     

Specific activation of brain cortical areas in response to stimulation of the support receptors in healthy subjects and patients with focal lesions of the CNS

The space medicine data on the nature of motor disorders suggest an important role of the support inputs in the control of mammalian tonic and postural systems. Progress in functional magnetic resonance tomography (fMRT) makes it possible to perform in vivo analysis of various brain areas during stimulation of the support afferentation. Under these conditions, specific activation of the brain cortical areas was studied in 19 healthy subjects (with the mean age of 38 ± 15.13 years) and 23 patients (with the mean age of 53 ± 9.07 years) with focal CNS lesions (cortical-subcortical ischemic stroke). During scanning of subjects, the support areas of the soles of the feet were stimulated using a block design to simulate slow walking. In healthy subjects, significant activation was recorded (p < 0.05 at the cluster level) in the primary somatosensory cortex, premotor and dorsolateral prefrontal cortex, and insular lobe. In patients that had had a stroke, activation of the locomotion-controlling supraspinal systems clearly depended on the stage of the disease. In patients with a cortical-subcortical stroke, the pattern of contralateral activation of the sensorimotor locomotion predominated during motility rehabilitation.     

Radiologic diagnosis of focal liver lesions

The paper is concerned with analysis of the results of combined investigation of 54 patients with focal liver lesions. USI, CT, angiography and radionuclide scintigraphy were performed. The diagnostic efficacy of USI and CT was 94.4 and 90.7%, respectively, that of scintigraphy was 68.5%, that of angiography was 55.5%. A scheme of the effective use of radiation methods in the diagnosis of sizable formations of the liver was worked out.     

Fine needle aspiration of focal liver lesions

Fourteen percutaneous fine needle aspirates (FNAs) of focal liver lesions performed under ultrasound guidance at the Sultan Qaboos University Hospital (SQUH), Oman, between January 1991 and October 1992, are presented. Ten of these were cytologically diagnosed as hepatocellular carcinomas (HCC). the patients' ages ranged from 50 to 70 years and eight of these were males. the important diagnostic cytological criteria of HCC were found to be increased nucleocytoplasmic (N/C) ratio, trabecular pattern, atypical naked nuclei, bile production by malignant hepatocytes and absence of bile duct epithelium. Carcinoembryonic antigen (CEA) positivity of bile canaliculi by cross-reaction with biliary glycoprotein I (BGP I) made possible the differentiation of HCC from metastases. We stress the importance of cell blocks as these often constitute microbiopsies. Ultrasound-guided FNA of focal liver lesions is recommended as a simple, easy and quick procedure.     

Prioritization of liver MRI for distinguishing focal lesions

Liver cancer is one of the leading causes of cancer-related mortality worldwide.Magnetic resonance imaging(MRI) is a non-invasive imaging technique that is often used by radiologists for diagnosis and surgical planning.Analysis of a large amount of liver MRI data for each patient limits the radiologist's efficiency and may lead to misdiagnoses.The redundant MRI data,especially from dynamic contrast enhanced(DCE) sequences,is also a bottleneck in transmitting the images via the internet or PACS for remote consultancy in a reasonable amount of time.This study included 25 patients(aged between 20 and 70years) with liver cysts(seven cases),hemangiomas(eight cases),or hepatic cell carcinomas(10 cases).DCE T1 WI MRI was performed for all the patients.The diagnosis reference included typical MRI findings and post-surgery pathology.The methods were as follows:(i) MRI sequence pre-processing based on large vessels variation level set method to remove non-liver parts from MRI images;(ii) human visual model features(luminance,motion,and contour) extraction and fusion;(iii) anomaly-based MRI ranking;and(iv) methods assessment with the 25 patients' DCE MRI data.The prioritization methods applied to the DCE images could automatically assimilate and determine the content of the medical images,identifying the liver cysts,hemangiomas,and carcinomas.The average uniformity between radiologists and prioritization with the proposed method was 0.805,0.838,and0.818 for cysts,hemangiomas,and carcinomas,respectively,which indicates that the proposed method is an efficient method for liver DCE image prioritization.     

On imputing function to structure from the behavioural effects of brain lesions

What is the link, if any, between the patterns of connections in the brain and the behavioural effects of localized brain lesions? We explored this question in four related ways. First, we investigated the distribution of activity decrements that followed simulated damage to elements of the thalamocortical network, using integrative mechanisms that have recently been used to successfully relate connection data to information on the spread of activation, and to account simultaneously for a variety of lesion effects. Second, we examined the consequences of the patterns of decrement seen in the simulation for each type of inference that has been employed to impute function to structure on the basis of the effects of brain lesions. Every variety of conventional inference, including double dissociation, readily misattributed function to structure. Third, we tried to derive a more reliable framework of inference for imputing function to structure, by clarifying concepts of function, and exploring a more formal framework, in which knowledge of connectivity is necessary but insufficient, based on concepts capable of mathematical specification. Fourth, we applied this framework to inferences about function relating to a simple network that reproduces intact, lesioned and paradoxically restored orientating behaviour. Lesion effects could be used to recover detailed and reliable information on which structures contributed to particular functions in this simple network. Finally, we explored how the effects of brain lesions and this formal approach could be used in conjunction with information from multiple neuroscience methodologies to develop a practical and reliable approach to inferring the functional roles of brain structures.     

Treatment with LXR agonists after focal cerebral ischemia prevents brain damage

Stroke is characterized by massive inflammation in areas surrounding the injury that magnifies damage to the brain. The liver X receptors (LXRs) are nuclear receptors that regulate cholesterol, lipid, and glucose metabolism. Synthetic LXR agonists have potent anti-inflammatory properties in a variety of settings, including neuroinflammation. However, the ability of LXR agonists to suppress stroke-associated inflammation has not been evaluated. Here, we have used time-lapse magnetic resonance imaging (MRI) to show that a single dose of an LXR ligand administered post-injury dramatically reduces brain damage in a model of acute brain ischemia. Neuroprotection was associated with suppression of neuroinflammation.