Emotional Facial Expression Detection in the Peripheral Visual Field

BACKGROUND: In everyday life, signals of danger, such as aversive facial expressions, usually appear in the peripheral visual field. Although facial expression processing in central vision has been extensively studied, this processing in peripheral vision has been poorly studied. METHODOLOGY/PRINCIPAL FINDINGS: Using behavioral measures, we explored the human ability to detect fear and disgust vs. neutral expressions and compared it to the ability to discriminate between genders at eccentricities up to 40°. Responses were faster for the detection of emotion compared to gender. Emotion was detected from fearful faces up to 40° of eccentricity. CONCLUSIONS: Our results demonstrate the human ability to detect facial expressions presented in the far periphery up to 40° of eccentricity. The increasing advantage of emotion compared to gender processing with increasing eccentricity might reflect a major implication of the magnocellular visual pathway in facial expression processing. This advantage may suggest that emotion detection, relative to gender identification, is less impacted by visual acuity and within-face crowding in the periphery. These results are consistent with specific and automatic processing of danger-related information, which may drive attention to those messages and allow for a fast behavioral reaction

Influence of Low-Level Stimulus Features, Task Dependent Factors, and Spatial Biases on Overt Visual Attention

Visual attention is thought to be driven by the interplay between low-level visual features and task dependent information content of local image regions, as well as by spatial viewing biases. Though dependent on experimental paradigms and model assumptions, this idea has given rise to varying claims that either bottom-up or top-down mechanisms dominate visual attention. To contribute toward a resolution of this discussion, here we quantify the influence of these factors and their relative importance in a set of classification tasks. Our stimuli consist of individual image patches (bubbles). For each bubble we derive three measures: a measure of salience based on low-level stimulus features, a measure of salience based on the task dependent information content derived from our subjects' classification responses and a measure of salience based on spatial viewing biases. Furthermore, we measure the empirical salience of each bubble based on our subjects' measured eye gazes thus characterizing the overt visual attention each bubble receives. A multivariate linear model relates the three salience measures to overt visual attention. It reveals that all three salience measures contribute significantly. The effect of spatial viewing biases is highest and rather constant in different tasks. The contribution of task dependent information is a close runner-up. Specifically, in a standardized task of judging facial expressions it scores highly. The contribution of low-level features is, on average, somewhat lower. However, in a prototypical search task, without an available template, it makes a strong contribution on par with the two other measures. Finally, the contributions of the three factors are only slightly redundant, and the semi-partial correlation coefficients are only slightly lower than the coefficients for full correlations. These data provide evidence that all three measures make significant and independent contributions and that none can be neglected in a model of human overt visual attention

Control of mechanical pain hypersensitivity in mice through ligand-targeted photoablation of TrkB-positive sensory neurons

Mechanical allodynia is a major symptom of neuropathic pain whereby innocuous touch evokes severe pain. Here we identify a population of peripheral sensory neurons expressing TrkB that are both necessary and sufficient for producing pain from light touch after nerve injury in mice. Mice in which TrkB-Cre-expressing neurons are ablated are less sensitive to the lightest touch under basal conditions, and fail to develop mechanical allodynia in a model of neuropathic pain. Moreover, selective optogenetic activation of these neurons after nerve injury evokes marked nociceptive behavior. Using a phototherapeutic approach based upon BDNF, the ligand for TrkB, we perform molecule-guided laser ablation of these neurons and achieve long-term retraction of TrkB-positive neurons from the skin and pronounced reversal of mechanical allodynia across multiple types of neuropathic pain. Thus we identify the peripheral neurons which transmit pain from light touch and uncover a novel pharmacological strategy for its treatment

Essential omega-3 fatty acids tune microglial phagocytosis of synaptic elements in the mouse developing brain

AbstractOmega-3 fatty acids (n-3 PUFAs) are essential for the functional maturation of the brain. Westernization of dietary habits in both developed and developing countries is accompanied by a progressive reduction in dietary intake of n-3 PUFAs. Low maternal intake of n-3 PUFAs has been linked to neurodevelopmental diseases in Humans. However, the n-3 PUFAs deficiency-mediated mechanisms affecting the development of the central nervous system are poorly understood. Active microglial engulfment of synapses regulates brain development. Impaired synaptic pruning is associated with several neurodevelopmental disorders. Here, we identify a molecular mechanism for detrimental effects of low maternal n-3 PUFA intake on hippocampal development in mice. Our results show that maternal dietary n-3 PUFA deficiency increases microglia-mediated phagocytosis of synaptic elements in the rodent developing hippocampus, partly through the activation of 12/15-lipoxygenase (LOX)/12-HETE signaling, altering neuronal morphology and affecting cognitive performance of the offspring. These findings provide a mechanistic insight into neurodevelopmental defects caused by maternal n-3 PUFAs dietary deficiency.Infrastructure de Recherche Translationnelle pour les Biothérapies en NeurosciencesProgram Initiative d’Excellenc

Update on the CGIAR reform process

COLLECTIVE ACTION NEWS is an e-publication of the CGIAR’s Regional Collective Action in Eastern and Southern Afric

Criblage des varietes des riz de bas-fond cultivees dans le departement de l’alibori pour leur resistance a la panachure jaune (RYMV)

La panachure jaune du riz (RYMV) constitue l’une des majeures contraintes biotiques à la riziculture irriguée et de bas-fond en Afrique. Au Bénin et en particulier dans le département de l’Alibori, le RYMV provoque d’énormes pertes de rendement. Cette étude a été initiée pour évaluer la réaction des variétés locales de l’Alibori au Bénin sous la pression de 4 isolats de RYMV.Sept variétés de riz (WITA 4, ADNY 11, Béris 21, IRAT 127, INARIS 88 , Gambiaka, locale Bagnon) couramment cultivées dans les périmètres irrigués et dans les bas-fonds du département de l’Alibori au Nord-Est du Bénin ont été soumises sous serre, à l’infection de quatre souches de RYMV d’origine béninoise. La période d’incubation, la sévérité de la maladie et la réduction de la hauteur des plants sont les paramètres mesurés, et les variétés Giganté et Bouaké 189 ont été respectivement utilisées comme témoins de résistance et de sensibilité.La plus courte durée d’incubation (9 jours) de la panachure jaune a été induite par l’isolat bc4 sur la variété Gambiaka. De toutes les variétés, Locale Bagnon, WITA 4, ADNY 11, IRAT 127 et INARIS 88 ont été modérément sensibles, alors que Béris 21 et Gambiaka ont été très sensibles. Les isolats bc3 et bc4 se sont révélés hautement pathogènes, tandis que l’isolat bc2 est faiblement pathogène.Mots clés: RYMV, variété, pathogénicité, résistance, Alibori, BéninEnglish AbstractRYMV disease is one of the major biotic constraints to irrigated and lowland rice production in Africa. In Benin and particularly in the department of Alibori, RYMV is causing important yield losses to farmers. This study was conducted to evaluate local genotypes under the pressure of 4 isolates of RYMV.Seven rice genotypes (WITA 4, ADNY 11, Beris 21, IRAT 127 , INARIS 88 , Gambiaka, Locale Bagnon) commonly grown in the irrigated and lowlands perimeters in the department of Alibori in northeast - Benin were r screened for resistance to RYMV. Four RYMV strains originated from Benin were used to inoculate the plants mechanically 21 DAS. Incubation period, disease severity and plant height reduction were determined, and the genotypes Giganté and Bouaké 189 were respectively used as resistance and susceptible controls.RYMV had the shortest incubation period of 9 days with the isolate bc4 on the genotype Gambiaka. Genotype Beris 21 was most affected by plant height reduction.Overall, genotypes Bagnon, WITA 4, ADNY 11, IRAT 127 and INARIS 88 were classified as moderately sensitive, while Béris 21 and Gambiaka were considered highly sensitive. The used isolates differed in their pathogenicity, with isolates bc3 and bc4 being highly pathogenic,while isolate bc2 was low pathogenic.Keywords: RYMV, variety, pathogenicity, resistance, Alibori - Beni