Coherent motion pops out during smooth pursuit

Stimulus motion is a prominent feature that is used by the visual system to segment figure from ground and perceptually bind widely separated objects. Pursuit eye movements can be influenced by such perceptual grouping processes. We have examined the subjects' ability to detect small amounts of coherent motion in random dot kinematograms during pursuit. We compared performance on tests of coherent motion perception while subjects fixated a stationary spot or while they tracked a moving target. The results indicate that smooth pursuit can improve subjects' ability to detect the presence of coherent motion. We tentatively propose that an efference copy of the eye movement signal can enhance the ability of the visual system to detect correlations between sparsely placed targets among noisy distractors

Changes in cortical activation during mirror reading before and after training: an fMRI study of procedural learning

The neural correlates of procedural learning were studied using functional magnetic resonance imaging (fMRI) and the mirror reading paradigm. The aim of the study was to investigate a presumed learning-related change of activation in cortical areas that are involved in the performance of a nonmotor skill. Changes in cortical blood oxygenation contrast were recorded in 10 healthy subjects while they alternatively read visually presented single mirror script words and normal script words. Responses in naive subjects were compared to those acquired after training of mirror script reading. The acquisition volume included the motor and premotor cortex, the parietal lobe and the occipital lobe including its inferior aspects. Striate and extrastriate visual areas, associative parietal cortex and the premotor cortex were bilaterally active during normal and mirror script reading. Significantly stronger activation during mirror reading was seen in BA7 and 40 (parietal associative cortex) and in BA6 (corresponding to the frontal eye fields). Simultaneous eye movement recordings indicated that activation in BA6 was related to processing components other than saccade frequency. After training, BA6 and BA7 exhibited a decrease of activation during mirror reading that significantly exceeded nonspecific changes observed in the normal script control condition. The present findings confirm the hypothesis of practice-related decrease of activation in task-related cortical areas during nonmotor procedural learning

Event-related fMRI responses in the human frontal eye fields in a randomized pro- and antisaccade task

We examined whether the frontal eye fields (FEF) are involved in the suppression of reflexive saccades. Simultaneous recording of horizontal eye movements and functional magnetic resonance imaging enabled us to perform a randomized pro- and antisaccade task and to sort blood oxygenation level dependent (BOLD) time series on the basis of task performance. Saccadic reaction time distributions were comparable across tasks indicating a similar effort in preprocessing of the saccades. Furthermore, we found similar BOLD activation in FEF during both correctly performed pro- and antisaccades. Frontal eye field activation started prior to target presentation and saccade generation. While we observed only few erroneous antisaccades, these were associated with a decrease in BOLD activity prior to target presentation, and increased BOLD activity after target presentation relative to correctly performed antisaccades. These findings are consistent with a role of the FEF in the suppression of reflexive saccades. The increase in activity after target presentation for antisaccade errors can only be indirectly linked to such a role but may also reflect activity related to the generation of a correction saccade. Frontal eye field BOLD activity may further represent general arousal, preparatory set, shortterm memory, or salience-map related activity

Human sFLT1 Leads to Severe Changes in Placental Differentiation and Vascularization in a Transgenic hsFLT1/rtTA FGR Mouse Model

The anti-angiogenic soluble fms-like tyrosine kinase 1 (sFLT1) is one of the candidates in the progression of preeclampsia, often associated with fetal growth restriction (FGR). Therapeutic agents against preeclampsia with/without FGR, as well as adequate transgenic sFLT1 mouse models for testing such agents, are still missing. Much is known about sFLT1–mediated endothelial dysfunction in several tissues; however, the influence of sFLT1 on placental and fetal development is currently unknown. We hypothesize that sFLT1 is involved in the progression of FGR by influencing placental differentiation and vascularization and is a prime candidate for interventional strategies. Therefore, we generated transgenic inducible human sFLT1/reverse tetracycline-controlled transactivator (hsFLT1/rtTA) mice, in which hsFLT1 is ubiquitously overexpressed during pregnancy in dams and according to the genetics in hsFLT1/rtTA homozygous and heterozygous fetuses. Induction of hsFLT1 led to elevated hsFLT1 levels in the serum of dams and on mRNA level in all placentas and hetero-/homozygous fetuses, resulting in FGR in all fetuses at term. The strongest effects in respect to FGR were observed in the hsFLT1/rtTA homozygous fetuses, which exhibited the highest hsFLT1 levels. Only fetal hsFLT1 expression led to impaired placental morphology characterized by reduced placental efficiency, enlarged maternal sinusoids, reduced fetal capillaries, and impaired labyrinthine differentiation, associated with increased apoptosis. Besides impaired placental vascularization, the expression of several transporter systems, such as glucose transporter 1 and 3 (Glut-1; Glut-3); amino acid transporters, solute carrier family 38, member one and two (Slc38a1; Slc38a2); and most severely the fatty acid translocase Cd36 and fatty acid binding protein 3 (Fabp3) was reduced upon hsFLT1 expression, associated with an accumulation of phospholipids in the maternal serum. Moreover, the Vegf pathway showed alterations, resulting in reduced Vegf, Vegfb, and Plgf protein levels and increased Bad and Caspase 9 mRNA levels. We suggest that hsFLT1 exerts an inhibitory influence on placental vascularization by reducing Vegf signaling, which leads to apoptosis in fetal vessels, impairing placental differentiation, and the nutrient exchange function of the labyrinth. These effects were more pronounced when both the dam and the fetus expressed hsFLT1 and ultimately result in FGR and resemble the preeclamptic phenotype in humans

Optic Flow Stimuli in and Near the Visual Field Centre: A Group fMRI Study of Motion Sensitive Regions

Motion stimuli in one visual hemifield activate human primary visual areas of the contralateral side, but suppress activity of the corresponding ipsilateral regions. While hemifield motion is rare in everyday life, motion in both hemifields occurs regularly whenever we move. Consequently, during motion primary visual regions should simultaneously receive excitatory and inhibitory inputs. A comparison of primary and higher visual cortex activations induced by bilateral and unilateral motion stimuli is missing up to now. Many motion studies focused on the MT+ complex in the parieto-occipito-temporal cortex. In single human subjects MT+ has been subdivided in area MT, which was activated by motion stimuli in the contralateral visual field, and area MST, which responded to motion in both the contra- and ipsilateral field. In this study we investigated the cortical activation when excitatory and inhibitory inputs interfere with each other in primary visual regions and we present for the first time group results of the MT+ subregions, allowing for comparisons with the group results of other motion processing studies. Using functional magnetic resonance imaging (fMRI), we investigated whole brain activations in a large group of healthy humans by applying optic flow stimuli in and near the visual field centre and performed a second level analysis. Primary visual areas were activated exclusively by motion in the contralateral field but to our surprise not by central flow fields. Inhibitory inputs to primary visual regions appear to cancel simultaneously occurring excitatory inputs during central flow field stimulation. Within MT+ we identified two subregions. Putative area MST (pMST) was activated by ipsi- and contralateral stimulation and located in the anterior part of MT+. The second subregion was located in the more posterior part of MT+ (putative area MT, pMT)

Система автоматического регулирования температуры в производственном помещении

САР температуры в помещении необходима для быстрого восстановления температурного режима в помещении чего не обеспечивает существующее центральное отопление.Позволяет улучшить качество регулирования температурного баланса. Цель работы – Оснащение воздушного отопительного агрегата системой автоматического управления. В процессе исследования проводились Анализ работы САУ вентиляционных систем, анализ построения САР температуры вентиляционных систем. В результате исследования Была разработана структурная и функциональная схемы САР температуры отопительного агрегата, а также алгоритм управления САР.ACS of temperature is indoors necessary for fast restoration of temperature condition in what doesn't provide the existing central heating. Allows to improve quality of regulation of temperature balance. The aim of the work is Vehicle air heating unit automatic control system. In the process of investigation the Analysis of the work of the ACS ventilation systems, analysis of building SAR temperature ventilation systems. The study was developed by structural and functional scheme of the SAR temperature of the heating unit and the control algorithm of the SAR