1,174 research outputs found

    The cerebellum and motor dysfunction in neuropsychiatric disorders

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    The cerebellum is densely interconnected with sensory-motor areas of the cerebral cortex, and in man, the great expansion of the association areas of cerebral cortex is also paralleled by an expansion of the lateral cerebellar hemispheres. It is therefore likely that these circuits contribute to non-motor cognitive functions, but this is still a controversial issue. One approach is to examine evidence from neuropsychiatric disorders of cerebellar involvement. In this review, we narrow this search to test whether there is evidence of motor dysfunction associated with neuropsychiatric disorders consistent with disruption of cerebellar motor function. While we do find such evidence, especially in autism, schizophrenia and dyslexia, we caution that the restricted set of motor symptoms does not suggest global cerebellar dysfunction. Moreover, these symptoms may also reflect involvement of other, extra-cerebellar circuits and detailed examination of specific sub groups of individuals within each disorder may help to relate such motor symptoms to cerebellar morphology

    Drawing cartoon faces - a functional imaging study of the cognitive neuroscience of drawing

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    We report a functional imaging study of drawing cartoon faces. Normal, untrained participants were scanned while viewing simple black and white cartoon line-drawings of human faces, retaining them for a short memory interval, and then drawing them without vision of their hand or the paper. Specific encoding and retention of information about the faces was tested for by contrasting these two stages (with display of cartoon faces) against the exploration and retention of random dot stimuli. Drawing was contrasted between conditions in which only memory of a previously viewed face was available versus a condition in which both memory and simultaneous viewing of the cartoon was possible, and versus drawing of a new, previously unseen, face. We show that the encoding of cartoon faces powerfully activates the face sensitive areas of the lateral occipital cortex and the fusiform gyrus, but there is no significant activation in these areas during the retention interval. Activity in both areas was also high when drawing the displayed cartoons. Drawing from memory activates areas in posterior parietal cortex and frontal areas. This activity is consistent with the encoding and retention of the spatial information about the face to be drawn as a visuo-motor action plan, either representing a series of targets for ocular fixation or as spatial targets for the drawing actio

    Analysis of changes in leg volume parameters, and orthostatic tolerance in response to lower body negative pressure during 59 days exposure to zero gravity Skylab 3

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    The cardiovascular responses of the Apollo crewmen associated with postflight evaluations indicate varying decrements of orthostatic tolerance. The postflight changes indicate a slightly diminished ability to the cardiovascular system to function effectively against gravity following exposure to weightlessness. The objective of the Skylab LBNP experiments (M092) was to provide information about the magnitude and time course of the cardiovascular changes associated with prolonged periods of exposure to weightlessness. This report details the equipment, signal processing and analysis of the leg volume data obtained from the M092 experiment of the Skylab 3 Mission

    "Yangambi km5" (Musa AAA, Ibota subgroup) : a possible source of resistance to Radopholus similis and Pratylenchus goodeyi

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    Des études en pot et en plein champ ont été conduites au Cameroun pour comparer la sensibilité du cultivar "Yangambi km5" à #Radopholus similis à celle des autres #Musa triploïdes et évaluer son comportement vis-à-vis de #Pratylenchus goodeyi. Les résultats des comptages de nématodes au champ effectués tous les 2 mois pendant 2 ans ont montré que les populations de #R. similis sont significativement plus faibles sur "Yangambi km5" que sur les autres cultivars. L'évaluation en pot de l'incidence de la concentration de l'inoculum sur le degré de résistance du "Yangambi km5" à #R. similis n'a révélé aucun effet significatif alors que sur le cultivar sensible "French Sombre", nous avons observé des niveaux de populations et de dégâts plus importants avec l'augmentation de l'inoculum. Le développement de #R. similis sur "Yangambi km5" s'est révélé plus faible que sur "French Sombre". "Yangambi km5" s'est également montré moins sensible que "French Sombre" aux attaques de #P. goodeyi$. (Résumé d'auteur

    Determination of cardiac size from chest roentgenograms following Skylab missions

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    Decreased cardiothoracic transverse diameter ratios following Mercury, Gemini and Apollo space flights have been reported previously. To evaluate further changes in cardiac size, standard posteroanterior chest films in systole and diastole were obtained before flight and within a few hours after recovery on each of the Skylab astronauts. Postflight chest X-rays were visually compared to the preflight roentgenograms for possible changes in pulmonary vasculature, lung parenchyma, bony or soft tissue structures. From these roentgenograms the following measurements were obtained: cardiac and thoracic transverse diameters, cardiothoracic transverse diameter ratio, cardiac area from the product of both diagonal diameters, cardiac silhouette area by planimetry, thoracic cage area and cardiothoracic area ratio. The postflight frontal cardiac silhouette sizes were significantly decreased when compared with the respective preflight values (P0.05 or 0.01). The observed changes are thought to be related to postflight decrease in the intracardiac chamber volume

    Drawing cartoon faces - a functional imaging study of the cognitive neuroscience of drawing.

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    We report a functional imaging study of drawing cartoon faces. Normal, untrained participants were scanned while viewing simple black and white cartoon line-drawings of human faces, retaining them for a short memory interval, and then drawing them without vision of their hand or the paper. Specific encoding and retention of information about the faces was tested for by contrasting these two stages (with display of cartoon faces) against the exploration and retention of random dot stimuli. Drawing was contrasted between conditions in which only memory of a previously viewed face was available versus a condition in which both memory and simultaneous viewing of the cartoon was possible, and versus drawing of a new, previously unseen, face. We show that the encoding of cartoon faces powerfully activates the face sensitive areas of the lateral occipital cortex and the fusiform gyrus, but there is no significant activation in these areas during the retention interval. Activity in both areas was also high when drawing the displayed cartoons. Drawing from memory activates areas in posterior parietal cortex and frontal areas. This activity is consistent with the encoding and retention of the spatial information about the face to be drawn as a visuo-motor action plan, either representing a series of targets for ocular fixation or as spatial targets for the drawing action

    Effects of Agency on Movement Interference During Observation of a Moving Dot Stimulus

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    Human movement performance is subject to interference if the performer simultaneously observes an incongruent action. It has been proposed that this phenomenon is due to motor contagion during simultaneous movement performance–observation, with coactivation of shared action performance and action observation circuitry in the premotor cortex. The present experiments compared the interference effect during observation of a moving person with observation of moving dot stimuli: The dot display followed either a biologically plausible or implausible velocity profile. Interference effects due to dot observation were present for both biological and nonbiological velocity profiles when the participants were informed that they were observing prerecorded human movement and were absent when the dot motion was described as computer generated. These results suggest that the observer's belief regarding the origin of the dot motion (human–computer generated) modulates the processing of the dot movement stimuli on their later integration within the motor system, such that the belief regarding their biological origin is a more important determinant of interference effects than the stimulus kinematics

    Water monitoring with hyperspectral techniques

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    1 - The poor of the world depends directly on water and other natural resources for their livelihoods. Water resources must therefore be managed in a sustainable manner in order to maintain the economic, social and environmental functions and to contribute to the livelihoods of people. 2 - Advancements in sensor technologies and processing algorithms have resulted in technical capabilities that can record and identify Earth surface materials based on the interaction of electromagnetic energy with the molecular structure of the material being sensed. 3 - Non-destructive and operative methodologies (NIR and Raman) will be tested through field surveys and laboratory analysis using Aquaphotomics approach. This approach requires precise measuring and mapping capabilities at field level of key data at a sufficient level of accuracy depending on the availability of equipment that must be also operated at a cost-effective way
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