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The extent of correlation and the latency of evoked potentials to sound, recorded bilaterally in the frontal cortex and lateral hypothalamus of cats, were studied at different stages of the acquisition of an operant food-related reflex and during sudden transfer to 30% food reinforcement. High correlation coefficients between the evoked responses of the cortex and hypothalamus with left-sided dominance were seen in conditions of high levels of food motivation at the beginning of each experiment and in conditions of the high-probability appearance of the acquired conditioned reflex throughout the rest of the experiment. Comparison of the peak latencies of the early positive (P55-80) components of evoked potentials on the right and left sides showed that shorter latent periods were seen in the cortex on the left side at all behavioral stages, while this occurred (on the left side) in the hypothalamus only when the conditioned reflex was unfixed, while after fixation of the reflex and provision of 30% reinforcement, shorter latent periods were seen on the right side. It is concluded that the high level of left-sided correlation of evoked potentials in the hypothalamus was associated with the motivational and motor components of purposive behavior and was not associated with the emotional tension of the animals provoked by the disruption of the food reinforcement stereotype.  相似文献   
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The results of a comparative clinicopharmacological study of adalate, foridone, siskor and lomir effects on cerebral and peripheral blood flow are presented for 46 patients with arterial hypertension stage I-III. It was found that all the four drugs relieve tonicity and enhance blood flow in a. cerebri media and a. carotis communis. Lomir and adalate had more potent effects on central hemodynamics. A maximal dilating effect on regional peripheral arteries was observed after a single intake of siskor and adalate, while lomir's and foridone's single doses were weaker. In course treatment with the above drugs these differences are less.  相似文献   
48.
In children with periventricular leukomalacia (PVL), motor dysfunction is thought to be related to involvement of pyramidal tract fibres in the periventricular white matter. The purpose of the present study was to test this hypothesis. Thirteen former preterm adolescents with PVL, ten of whom were suffering from bilateral spastic cerebral palsy, were studied by MRI. The severity of pyramidal tract damage was assessed on semicoronal MRI reconstructions along anatomical landmarks of somatotopy in the precentral gyrus and the internal capsule; for comparison, the overall volume of cerebral white matter (determined by automated volumetry) served as a global measure of lesion severity. The motor dysfunction of each of the four extremities correlated much more strongly with the severity of pyramidal tract damage assessed on the respective MRI reconstruction (range of correlation coefficients, 0.647 to 0.922) than with the total volume of white matter (range of correlation coefficients, - 0.458 to - 0.212; Spearman). These findings corroborate the notion that an involvement of pyramidal tract fibres in the periventricular white matter is indeed a relevant factor for motor dysfunction in children with PVL.  相似文献   
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External imaging of nicotinic acetylcholine receptors (nAChRs) using techniques such as PET would help to clarify the roles of these receptors in the physiology and pathology of brain function. Here we report the results of quantitative PET studies of cerebral nAChRs with 2-[(18)F]fluoro-A-85380 (2-[(18)F]FA) in rhesus monkeys. Data from dynamic PET scans were analyzed using graphical methods. Binding potential (BP) values of 2.0, 0.4, 0.3, and 0.03 observed in the thalamus (Th), cortex (Cx), striatum (Str), and cerebellum (Cb), respectively, were consistent with the pattern of alpha(4)beta(2) nAChR distribution in monkey brain. The high value of 2-[(18)F]FA-specific binding in the rhesus monkey Th and low level of that in Cb compared with nonspecific accumulation of radioactivity in these structures allowed use of Cb as a reference region for calculation of BP and volume of distribution of specific binding (VDsb) in Th by graphical methods, both with and without the plasma input function. In contrast, estimation of 2-[(18)F]FA specific binding in low-receptor-density regions such as Cx and Str required assessment of nondisplaceable volume of distribution (VDnd) in a separate study and measurement of nonmetabolized radioligand concentrations in the plasma. For accurate quantitation of 2-[(18)F]FA-specific binding by graphical analysis, PET studies should last up to 7 h due to the slow kinetics of 2-[(18)F]FA brain distribution. Further, to avoid substantial underestimation in measured BP values the doses of administered 2-[(18)F]FA should not exceed 0.1 nmol/kg body weight. The findings suggest that 2-[(18)F]FA is a promising ligand for quantitation of nAChRs in human brain.  相似文献   
50.
The paper presents data on poor working conditions at the foam polyurethane (FPU) plant, which cause specific clinical manifestations in workers, indirectly exert their children's health. The children of FPU plant workers have lower physical development, diseases of immune genesis (glumeronephritis, bronchial asthma, allergic manifestations, etc.) more frequently, higher incidence of dental caries, enamel hypoplasia in the presence of altered mineral metabolism.  相似文献   
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