2,347 research outputs found

    Exploring number space by random digit generation

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    There is some evidence that human subjects preferentially select small numbers when asked to sample numbers from large intervals "at random”. A retrospective analysis of single digit frequencies in 16 independent experiments with the Mental Dice Task (generation of digits 1-6 during 1min) confirmed the occurrence of small-number biases (SNBs) in 488 healthy subjects. A subset of these experiments suggested a spatial nature of this bias in the sense of a "leftward” shift along the number line. First, individual SNBs were correlated with leftward deviations in a number line bisection task (but unrelated to the bisection of physical lines). Second, in 20 men, the magnitude of SNBs significantly correlated with leftward attentional biases in the judgment of chimeric faces. Finally, cognitive activation of the right hemisphere enhanced SNBs in 20 different men, while left hemisphere activation reduced them. Together, these findings provide support for a spatial component in random number generation. Specifically, they allow an interpretation of SNBs in terms of "pseudoneglect in number space.” We recommend the use of random digit generation for future explorations of spatial-attentional asymmetries in numerical processing and discuss methodological issues relevant to prospective design

    Late laying hens deposit dietary antioxidants preferentially in the egg and not in the body

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    The allocation of nutrients in the metabolism of laying hens favors the egg over the body. It is unclear whether this programming also includes micronutrients and antioxidants. This was tested with five by seven 76-wk-old Heisdorf & Nelson Brown Nick layers. They were fed a basal diet low in antioxidants either unchanged (control) or supplemented with 40 IU of α-tocopherylacetate/kg of diet (vitamin E) or 2.5% chokeberry pomace, rose hip, or sage in the last 4 wk before slaughter. The traits measured were subjected to ANOVA. The additives did not affect ADFI, performance, egg quality, carcass, or meat quality. Yolk tocopherol contents were higher with vitamin E and sage compared with control and rose hip treatments. Oxidative stability was more affected in egg yolk powder than in the meat. After 12 wk of storage, yolks from vitamin E-treated hens were lowest in TBA levels (5.0 mg of malondialdehyde/kg), followed by chokeberry (8.7) and sage (8.8). Rose hip (18.1) and control (18.9) treatments were similar. In meat, TBA was slightly decreased after 9 d of storage in meat from chokeberry- and sage-supplemented hens (contrast analysis). In conclusion, antioxidant deposition to the egg seems to be part of the genetic determination of the hen. Adding antioxidants is therefore interesting for layer nutrition in general, and herbal additives allow performing this in a natural way. The programming for partitioning, however, renders the strategic feeding of antioxidants before slaughter, with the goal to increase oxidative stability of spent hen meat rather inefficien

    Variation in left posterior parietal-motor cortex interhemispheric facilitation following right parietal continuous theta-burst stimulation in healthy adults

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    © 2016 IBRO. Spatial neglect is modeled on an imbalance of interhemispheric inhibition (IHI); however evidence is emerging that it may not explain neglect in all cases. The aim of this study was to investigate the IHI imbalance model of visual neglect in healthy adults, using paired pulse transcranial magnetic stimulation to probe excitability of projections from posterior parietal cortex (PPC) to contralateral primary motor cortex (M1) bilaterally. Motor-evoked potentials (MEPs) were recorded from the first dorsal interossei and facilitation was determined as ratio of conditioned to non-conditioned MEP amplitude. A laterality index reflecting the balance of excitability between the two hemispheres was calculated. A temporal order judgment task (TOJ) assessed visual attention. Continuous theta-burst stimulation was used to transiently suppress right parietal cortex activity and the effect on laterality and judgment task measured, along with associations between baseline and post stimulation measures. Stimulation had conflicting results on laterality, with most participants demonstrating an effect in the negative direction with no decrement in the TOJ task. Correlation analysis suggests a strong association between laterality direction and degree of facilitation of left PPC-to right M1 following stimulation (r = .902), with larger MEP facilitation at baseline demonstrating greater reduction (r = -.908). Findings indicate there was relative balance between the cortices at baseline but right PPC suppression did not evoke left PPC facilitation in most participants, contrary to the IHI imbalance model. Left M1 facilitation prior to stimulation may predict an individual's response to continuous theta-burst stimulation of right PPC

    Bisecting the mental number line in near and far space

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    Much evidence suggests that common posterior parietal mechanisms underlie the orientation of attention in physical space and along the mental number line. For example, the small leftward bias (pseudoneglect) found in paper-and-pencil line bisection is also found when participants "bisect" number pairs, estimating (without calculating) the number midway between two others. For bisection of physical lines, pseudoneglect has been found to shift rightward as lines are moved from near space (immediately surrounding the body) to far space. We investigated whether the presentation of stimuli in near or far space also modulated spatial attention for the mental number line. Participants bisected physical lines or number pairs presented at four distances (60, 120, 180, 240 cm). Clear rightward shifts in bias were observed for both tasks. Furthermore, the rate at which this shift occurred in the two tasks, as measured by least squares regression slopes, was significantly correlated across participants, suggesting that the transition from near to far distances induced a common modulation of lateral attention in physical and numerical space. These results demonstrate a tight coupling between number and physical space, and show that even such prototypically abstract concepts as number are modulated by our on-line interactions with the world

    Approaching stimuli bias attention in numerical space

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    Increasing evidence suggests that common mechanisms underlie the direction of attention in physical space and numerical space, along the mental number line. The small leftward bias (pseudoneglect) found on paper-and-pencil line bisection is also observed when participants ‘bisect’ number pairs, estimating (without calculating) the number midway between two others. Here we investigated the effect of stimulus motion on attention in numerical space. A two-frame apparent motion paradigm manipulating stimulus size was used to produce the impression that pairs of numbers were approaching (size increase from first to second frame), receding (size decrease), or not moving (no size change). The magnitude of pseudoneglect increased for approaching numbers, even when the final stimulus size was held constant. This result is consistent with previous findings that pseudoneglect in numerical space (as in physical space) increases as stimuli are brought closer to the participant. It also suggests that the perception of stimulus motion modulates attention over the mental number line and provides further support for a connection between the neural representations of physical space and number

    Toxicity in Neuronal Cells Caused by Cerebrospinal Fluid from Pneumococcaland Gram-Negative Meningitis

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    To identify neurotoxic factors in meningitis, a neuronal cell line (HN33.1) was exposed to cerebrospinal fluid (CSF) obtained from rabbits with pneumococcal meningitis or Escherichia coli meningitis or 2 h and 6 h after meningitis was induced by proinflammatory bacterial products (pneumococcal cell walls, endotoxin). CSF from all types of meningitis induced similar degrees of cytotoxicity. When a soluble tumor necrosis factor (TNF) receptor that completely blocked TNF-mediated toxicity at 10-7 M was used, all toxicity in meningitis caused by E. coli, endotoxin, or pneumococcal cell wall administration (2 h afterwards) was mediated by TNF. In contrast, CSF from animals with meningitis caused by live pneumococci or pneumococcal cell wall injection (6 h afterwards) retained cytotoxicity in the presence of the TNF receptor. Thus, in established pneumococcal meningitis, but not in the other forms of meningitis, TNF is not the only component toxic in this neuronal cell lin

    CONSTITUTIVE mRNA AND PROTEIN PRODUCTION OF MACROPHAGE COLONY-STIMULATING FACTOR BUT NOT OF OTHER CYTOKINES BY SYNOVIAL FIBROBLASTS FROM RHEUMATOID ARTHRITIS AND OSTEOARTHRITIS PATIENTS

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    This study analyses the mRNA and protein production and their regulation of macrophage colony-stimulating factor (M-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF), IL-8 and IL-6 by synovial fibroblasts obtained from patients with RA and OA. M-CSF was found to be produced constitutively as opposed to other cytokines. Stimulation of the cells with IL-1β caused a marked increase of GM-CSF, IL-8, IL-6 and as well as of M-CSF mRNA levels. In parallel, a time-dependent increase of M-CSF, GM-CSF, IL-8 and IL-6 protein production was observed. Among the cytokine mRNAs examined only that of M-CSF exhibited a pronounced stability in unstimulated synovial fibroblasts, whereas the other cytokines displayed short mRNA half-lives of 1-2 h. Induction by IL-1β markedly prolonged IL-8, IL-6 and GM-CSF mRNA half-lives to >8 h which indicates increased mRNA stability. These findings suggest that among the cytokines that are produced in the inflamed synovium M-CSF may be particularly important for sustaining long-term influx, activation and survival of mononuclear phagocytes. GM-CSF, IL-8 and IL-6, by contrast, may be more involved in more acute cellular response

    Algorithmic Complexity for Short Binary Strings Applied to Psychology: A Primer

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    Since human randomness production has been studied and widely used to assess executive functions (especially inhibition), many measures have been suggested to assess the degree to which a sequence is random-like. However, each of them focuses on one feature of randomness, leading authors to have to use multiple measures. Here we describe and advocate for the use of the accepted universal measure for randomness based on algorithmic complexity, by means of a novel previously presented technique using the the definition of algorithmic probability. A re-analysis of the classical Radio Zenith data in the light of the proposed measure and methodology is provided as a study case of an application.Comment: To appear in Behavior Research Method

    METHOTREXATE ACTION IN RHEUMATOID ARTHRITIS: STIMULATION OF CYTOKINE INHIBITOR AND INHIBITION OF CHEMOKINE PRODUCTION BY PERIPHERAL BLOOD MONONUCLEAR CELLS

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    This open label study examines whether methotrexate (MTX) treatment modulates ex vivo synthesis of interleukin-1 receptor antagonist (IL-lra), soluble tumour necrosis factor receptors(sTNFR p55 and p75), interleukin-1β (IL-1β), tumour necrosis factor α(TNF-α), interleukin-8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1) by peripheral blood mononuclear cells (PBMC} and whether changes reflect clinical response. Significant stimulation of IL-lra and sTNFR p75 as well as inhibition of IL-8 production of PBMC were associated with clinical improvement observed in patients treated with MTX. When defining the characteristics of patients at study entry retrospectively in responders and non-responders a significantly lower ratio of IL-lra :IL-1β production before and its increase upon treatment was associated with clinical response in 13 patients compared to five patients not responding to MTX. In addition, clinical improvement was associated with decreased synthesis of IL-1β, TNF-α and IL-8 induced by bacterial lipopolysaccharide, IL-1α and IL-1β in PBMC in vitro. These findings suggest that MTX therapy reverses the inflammatory type of rheumatoid arthritis (RA) blood mononuclear cells by stimulating cytokine inhibitor production while inhibiting inflammatory cytokine release at the same time. This may explain the powerful anti-inflammatory properties of low-dose MTX as observed in most RA patients. Pretreatment determination of the IL-lra: IL-1β ratio in PBMC may be predictive with regard to a favourable therapeutic response and therefore may be useful for the selection of RA patients to be treated with MT
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