Speed and Accuracy of Static Image Discrimination by Rats

When discriminating dynamic noisy sensory signals, human and primate subjects achieve higher accuracy when they take more time to decide, an effect attributed to accumulation of evidence over time to overcome neural noise. We measured the speed and accuracy of twelve freely behaving rats discriminating static, high contrast photographs of real-world objects for water reward in a self-paced task. Response latency was longer in correct trials compared to error trials. Discrimination accuracy increased with response latency over the range of 500-1200ms. We used morphs between previously learned images to vary the image similarity parametrically, and thereby modulate task difficulty from ceiling to chance. Over this range we find that rats take more time before responding in trials with more similar stimuli. We conclude that rats' perceptual decisions improve with time even in the absence of temporal information in the stimulus, and that rats modulate speed in response to discrimination difficulty to balance speed and accuracy

Unsettling sustainability: the poetics of discomfort

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ДІАГНОСТИКА КЛІЩОВИХ ІНФЕКЦІЙ У ВАГІТНИХ

The aim of the study – to determine the frequency of infection with B. burgdorferi sensu lato (s. l.), A. phagocytophilum, Babesia spp. and tick-borne encephalitis virus (ТВEV) of pregnant women in Ternopil region. Materials and Methods. 43 pregnant women at 22–27 weeks of pregnancy, who had pathology of pregnancy, were examined. Specific IgM and IgG antibodies to B. burgdorferi s.l. were determined in blood serum by ELISA test, as well as DNA of: B. burgdorferi s. l. and A. phagocytophilum; RNA of: Babesia spp. and TBEV in the blood of pregnant women by real-time PCR. Results and Discussion. Specific IgM and/or IgG antibodies to B. burgdorferi s. l. (B. burgdorferi sensu stricto, B. afzeli, B. garinii) by ELISA test were detected in the sera of 41.9 % of pregnant women. By PCR method DNA of B. burgdorferi s. l. found in the blood of 9.3 % in pregnant women; DNA of A. phagocytophilum – in 6.9 %, RNA of Babesia spp. – in 4.7 %, RNA TBEV – in 4.7 %. Сonclusion. Detection of nucleic acids of tick-borne infections in pregnant women with pathology of pregnancy probably indicates the possible involvement of these pathogens in the occurrence of this pathology. Pregnant women can become infected by consuming uncooked goat's and cattle milk.Цель исследования – установить частоту инфицирования B. burgdorferi sensu lato (s. l.), A. phagocytophilum, Babesia spp. и вирусом клещевого энцефалита (ВКЭ) беременных Тернопольщины. Материалы и методы. Обследовано 43 беременных на 22–27-й неделях беременности, которые имели патологию беременности. В сыворотке крови определяли специфические антитела классов IgM и IgG к B. burgdorferi s. l. методом ИФА, а также ДНК B. burgdorferi s. l, A. phagocytophilum и РНК Babesia spp. и ВКЕ в крови беременных с помощью ПЦР в режиме реального времени. Результаты исследования и их обсуждение. Специфические антитела IgM и/или IgG к B. burgdorferi s. l. (B. burgdorferi sensu stricto, B. afzeli, B. garinii) с помощью ИФА выявлено в сыворотках крови 41,9 % беременных. Методом ПЦР ДНК B. burgdorferi s. l. найдено в крови 9,3 % беременных, ДНК A. phagocytophilum – в 6,9 %, РНК Babesia spp. – у 4,7 %, РНК ВКЭ – у 4,7 %. Вывод. Выявление нуклеиновых кислот возбудителей клещевых инфекций у беременных с патологией беременности, вероятно, свидетельствует о возможной причастности отмеченных возбудителей к возникновению этой патологии. Возможно инфицирование беременных при употреблении термически не обработанного молока коз и крупного рогатого скота.Мета дослідження – з’ясувати частоту інфікування B. burgdorferi sensu lato (s. l.), A. phagocytophilum, Babesia spp. і вірусом кліщового енцефаліту (ВКЕ) вагітних Тернопільщини. Матеріали та методи. Обстежено 43 вагітних на 22–27-му тижнях вагітності, які мали патологію вагітності. В сироватці крові визначали специфічні антитіла класів IgM та IgG до B. burgdorferi s. l. методом ІФА, а також ДНК B. burgdorferi s. l., A. phagocytophilum та РНК Babesia spp. і ВКЕ в крові вагітних за допомогою ПЛР у режимі реального часу. Результати дослідження та їх обговорення. Специфічні антитіла IgM і/чи IgG до B. burgdorferi s. l. (B. burgdorferi sensu stricto, B. afzeli, B. garinii) за допомогою ІФА виявлено у сироватках крові 41,9 % вагітних. Методом ПЛР ДНК B. burgdorferi s. l. знайдено в крові 9,3 % вагітних; ДНК A. phagocytophilum – у 6,9 %, РНК Babesia spp. – у 4,7 %, РНК ВКЕ – у 4,7 %. Висновок. Виявлення нуклеїнових кислот збудників кліщових інфекцій у вагітних із патологією вагітності, ймовірно, свідчить про можливу причетність зазначених збудників до виникнення цієї патології. Можливе інфікування вагітних при вживанні термічно не обробленого молока кіз і великої рогатої худоби

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)

Significance of Elevated Blood Metal Ion Levels in Patients with Metal-on-Metal Prostheses: An Evaluation of Oxidative Stress Markers

It is widely known that cobalt and chromium ions can enhance the production of reactive oxygen species, known to be damaging to cells by disturbing their redox status and then generating oxidative stress. The aim of the present study was to determine if increased metal ion levels induce a state of oxidative stress in patients with metal-on-metal (MM) hip arthroplasty. Results indicated that there was no significant difference in the concentration of oxidative stress markers (total antioxidants, peroxides, and nitrated proteins) in the patients with MM bearings compared to patients without prostheses. The activity antioxidant enzymes was stable (catalase and glutathione peroxidase) or slightly decreased (superoxide dismutase and heme oxygenase-1) over time. This work is the first to determine the biological effects of metal ions released from MM hip implants with regards to mid-term systemic oxidative stress and showed that the increased levels of Co and Cr ions are not associated with significant oxidative stress damage in the plasma of patients with these implants

Changing Human Visual Field Organization from Early Visual to Extra-Occipital Cortex

BACKGROUND: The early visual areas have a clear topographic organization, such that adjacent parts of the cortical surface represent distinct yet adjacent parts of the contralateral visual field. We examined whether cortical regions outside occipital cortex show a similar organization. METHODOLOGY/PRINCIPAL FINDINGS: The BOLD responses to discrete visual field locations that varied in both polar angle and eccentricity were measured using two different tasks. As described previously, numerous occipital regions are both selective for the contralateral visual field and show topographic organization within that field. Extra-occipital regions are also selective for the contralateral visual field, but possess little (or no) topographic organization. A regional analysis demonstrates that this weak topography is not due to increased receptive field size in extra-occipital areas. CONCLUSIONS/SIGNIFICANCE: A number of extra-occipital areas are identified that are sensitive to visual field location. Neurons in these areas corresponding to different locations in the contralateral visual field do not demonstrate any regular or robust topographic organization, but appear instead to be intermixed on the cortical surface. This suggests a shift from processing that is predominately local in visual space, in occipital areas, to global, in extra-occipital areas. Global processing fits with a role for these extra-occipital areas in selecting a spatial locus for attention and/or eye-movements

Towards a framework for attention cueing in instructional animations: Guidelines for research and design

This paper examines the transferability of successful cueing approaches from text and static visualization research to animations. Theories of visual attention and learning as well as empirical evidence for the instructional effectiveness of attention cueing are reviewed and, based on Mayer’s theory of multimedia learning, a framework was developed for classifying three functions for cueing: (1) selection—cues guide attention to specific locations, (2) organization—cues emphasize structure, and (3) integration—cues explicate relations between and within elements. The framework was used to structure the discussion of studies on cueing in animations. It is concluded that attentional cues may facilitate the selection of information in animations and sometimes improve learning, whereas organizational and relational cueing requires more consideration on how to enhance understanding. Consequently, it is suggested to develop cues that work in animations rather than borrowing effective cues from static representations. Guidelines for future research on attention cueing in animations are presented

Integration of Sensory and Reward Information during Perceptual Decision-Making in Lateral Intraparietal Cortex (LIP) of the Macaque Monkey

Single neurons in cortical area LIP are known to carry information relevant to both sensory and value-based decisions that are reported by eye movements. It is not known, however, how sensory and value information are combined in LIP when individual decisions must be based on a combination of these variables. To investigate this issue, we conducted behavioral and electrophysiological experiments in rhesus monkeys during performance of a two-alternative, forced-choice discrimination of motion direction (sensory component). Monkeys reported each decision by making an eye movement to one of two visual targets associated with the two possible directions of motion. We introduced choice biases to the monkeys' decision process (value component) by randomly interleaving balanced reward conditions (equal reward value for the two choices) with unbalanced conditions (one alternative worth twice as much as the other). The monkeys' behavior, as well as that of most LIP neurons, reflected the influence of all relevant variables: the strength of the sensory information, the value of the target in the neuron's response field, and the value of the target outside the response field. Overall, detailed analysis and computer simulation reveal that our data are consistent with a two-stage drift diffusion model proposed by Diederich and Bussmeyer [1] for the effect of payoffs in the context of sensory discrimination tasks. Initial processing of payoff information strongly influences the starting point for the accumulation of sensory evidence, while exerting little if any effect on the rate of accumulation of sensory evidence

Towards an alternative testing strategy for nanomaterials used in nanomedicine: lessons from NanoTEST.

In spite of recent advances in describing the health outcomes of exposure to nanoparticles (NPs), it still remains unclear how exactly NPs interact with their cellular targets. Size, surface, mass, geometry, and composition may all play a beneficial role as well as causing toxicity. Concerns of scientists, politicians and the public about potential health hazards associated with NPs need to be answered. With the variety of exposure routes available, there is potential for NPs to reach every organ in the body but we know little about the impact this might have. The main objective of the FP7 NanoTEST project ( www.nanotest-fp7.eu ) was a better understanding of mechanisms of interactions of NPs employed in nanomedicine with cells, tissues and organs and to address critical issues relating to toxicity testing especially with respect to alternatives to tests on animals. Here we describe an approach towards alternative testing strategies for hazard and risk assessment of nanomaterials, highlighting the adaptation of standard methods demanded by the special physicochemical features of nanomaterials and bioavailability studies. The work has assessed a broad range of toxicity tests, cell models and NP types and concentrations taking into account the inherent impact of NP properties and the effects of changes in experimental conditions using well-characterized NPs. The results of the studies have been used to generate recommendations for a suitable and robust testing strategy which can be applied to new medical NPs as they are developed

Inhibitory Effects of Prior Low-dose X-irradiation on Ischemia-reperfusion Injury in Mouse Paw

We have reported that low-dose, unlike high-dose, irradiation enhanced antioxidation function and reduced oxidative damage. On the other hand, ischemia-reperfusion injury is induced by reactive oxygen species. In this study, we examined the inhibitory effects of prior low-dose X-irradiation on ischemia-reperfusion injury in mouse paw. BALB/c mice were irradiated by sham or 0.5 Gy of X-ray. At 4 hrs after irradiation, the left hind leg was bound 10 times with a rubber ring for 0.5, 1, or 2 hrs and the paw thickness was measured. Results show that the paw swelling thickness by ischemia for 0.5 hr was lower than that for 2 hrs. At 1 hr after reperfusion from ischemia for 1 hr, superoxide dismutase activity in serum was increased in those mice which received 0.5 Gy irradiation and in the case of the ischemia for 0.5 or 1 hr, the paw swelling thicknesses were inhibited by 0.5 Gy irradiation. In addition, interstitial edema in those mice which received 0.5 Gy irradiation was less than that in the mice which underwent by sham irradiation. These findings suggest that the ischemia-reperfusion injury is inhibited by the enhancement of antioxidation function by 0.5 Gy irradiation