Anticipatory Semantic Processes

Why anticipatory processes correspond to cognitive abilities of living systems? To be adapted to an environment, behaviors need at least i) internal representations of events occurring in the external environment; and ii) internal anticipations of possible events to occur in the external environment. Interactions of these two opposite but complementary cognitive properties lead to various patterns of experimental data on semantic processing. How to investigate dynamic semantic processes? Experimental studies in cognitive psychology offer several interests such as: i) the control of the semantic environment such as words embedded in sentences; ii) the methodological tools allowing the observation of anticipations and adapted oculomotor behavior during reading; and iii) the analyze of different anticipatory processes within the theoretical framework of semantic processing. What are the different types of semantic anticipations? Experimental data show that semantic anticipatory processes involve i) the coding in memory of sequences of words occurring in textual environments; ii) the anticipation of possible future words from currently perceived words; and iii) the selection of anticipated words as a function of the sequences of perceived words, achieved by anticipatory activations and inhibitory selection processes. How to modelize anticipatory semantic processes? Localist or distributed neural networks models can account for some types of semantic processes, anticipatory or not. Attractor neural networks coding temporal sequences are presented as good candidate for modeling anticipatory semantic processes, according to specific properties of the human brain such as i) auto-associative memory; ii) learning and memorization of sequences of patterns; and iii) anticipation of memorized patterns from previously perceived patterns

The influence of semantic context on initial eye landing sites in words

To determine the role of ongoing processing on eye guidance in reading, two studies examined the effects of semantic context on the eyes' initial landing position in words of different levels of processing diffculty. Results from both studies clearly indicate a shift of the initial fixation location towards the end of the words for words that can be predicted from a prior semantic context. However, shifts occur only in high-frequency words and with prior fixations close to the beginning of the target word. These results suggest that ongoing perceptual and linguistic processes can affect the decision of where to send the eyes next in reading. They are explained in terms of the easiness of processing associated with the target words when located in parafoveal vision. It is concluded that two critical factors might help observing effects of linguistic variables on initial landing sites, namely, the frequency of the target word and the position where the eyes are launched from as regards to the beginning of the target word. Results also provide evidence for an early locus of semantic context effects in reading

Attentional and Semantic Anticipations

Why are attentional processes important in the driving of anticipations? Anticipatory processes are fundamental cognitive abilities of living systems, in order to rapidly and accurately perceive new events in the environment, and to trigger adapted behaviors to the newly perceived events. To process anticipations adapted to sequences of various events in complex environments, the cognitive system must be able to run specific anticipations on the basis of selected relevant events. Then more attention must be given to events potentially relevant for the living system, compared to less important events. What are useful attentional factors in anticipatory processes? The relevance of events in the environment depend on the effects they can have on the survival of the living system. The cognitive system must then be able to detect relevant events to drive anticipations and to trigger adapted behaviors. The attention given to an event depends on i) its external physical relevance in the environment, such as time duration and visual quality, and ii) on its internal semantic relevance in memory, such as knowledge about the event (semantic field in memory) and anticipatory power (associative strength to anticipated associates). How can we model interactions between attentional and semantic anticipations? Specific types of distributed recurrent neural networks are able to code temporal sequences of events as associated attractors in memory. Particular learning protocol and spike rate transmission through synaptic associations allow the model presented to vary attentionally the amount of activation of anticipations (by activation or inhibition processes) as a function of the external and internal relevance of the perceived events. This type of model offers a unique opportunity to account for both anticipations and attention in unified terms of neural dynamics in a recurrent network

Machine Learning under the light of Phraseology expertise: use case of presidential speeches, De Gaulle -Hollande (1958-2016)

International audienceAuthor identification and text genesis have always been a hot topic for the statistical analysis of textual data community. Recent advances in machine learning have seen the emergence of machines competing state-of-the-art computational linguistic methods on specific natural language processing tasks (part-of-speech tagging, chunking and parsing, etc). In particular, Deep Linguistic Architectures are based on the knowledge of language speci-ficities such as grammar or semantic structure. These models are considered as the most competitive thanks to their assumed ability to capture syntax. However if those methods have proven their efficiency, their underlying mechanisms, both from a theoretical and an empirical analysis point of view, remains hard both to explicit and to maintain stable, which restricts their area of applications. Our work is enlightening mechanisms involved in deep architectures when applied to Natural Language Processing (NLP) tasks. The Query-By-Dropout-Committee (QBDC) algorithm is an active learning technique we have designed for deep architectures: it selects iteratively the most relevant samples to be added to the training set so that the model is improved the most when built from the new training set. However in this article, we do not go into details of the QBDC algorithm-as it has already been studied in the original QBDC article-but we rather confront the relevance of the sentences chosen by our active strategy to state of the art phraseology techniques. We have thus conducted experiments on the presidential discourses from presidents C. De Gaulle, N. Sarkozy and F. Hollande in order to exhibit the interest of our active deep learning method in terms of discourse author identification and to analyze the extracted linguistic patterns by our artificial approach compared to standard phraseology techniques.L'identification de l'auteur et la gen ese d'un texte ont toujours eté une question de tr es grand intérêt pour la com-munauté de l'analyse statistique des données textuelles. Les récentes avancées dans le domaine de l'apprentissage machine ont permis l'´ emergence d'algorithmes concurrençant les méthodes de linguistique computationnelles de l'´ etat de l'art pour des tâches spécifiques en traitement automatique du langage (´ etiquetage des parties du dis-cours, segmentation et l'analyse du texte, etc). En particulier, les architectures profondes pour la linguistique sont fondées sur la connaissance des spécificités linguistiques telles que la grammaire ou la structure sémantique. Ces mod eles sont considérés comme les plus compétitifs grâcè a leur capacité supposée de capturer la syntaxe. Toute-fois, si ces méthodes ont prouvé leur efficacité, leurs mécanismes sous-jacents, tant du point de vue théorique que du point de vue de l'analyse empirique, restent difficilè a la fois a expliciter et a maintenir stables, ce qui limite leur domaine d'application. Notre article visè a mettre enlumì ere certains des mécanismes impliqués dans l'apprentissage profond lorsqu'il est appliqué a des tâches de traitement automatique du langage (TAL). L'algorithme Query-By-Dropout-Committee (QBDC) est une technique d'apprentissage actif, nous avons conçu pour les architectures profondes : il sélectionne itérativement les echantillons les plus pertinents pour etre ajoutés a l'ensemble d'entrainement afin que le mod ele soit amélioré de façon optimale lorsqu'on il est mis a jour a partir du nouvel ensemble d'entrainement. Cependant, dans cet article, nous ne détaillons pas l'algorithme QBDC-qui a déj a ´ eté etudié dans l'article original sur QBDC-mais nous confrontons plutôt la pertinence des phrases choisies par notre stratégie active aux techniques de l'´ etat de l'art en phraséologie. Nous avons donc mené des expériences sur les discours présidentiels des présidents C. De Gaulle , N. Sarkozy et F. Hollande afin de présenter l' intérêt de notre méthode d'apprentissage profond actif en termes de d'identification de l'auteur d'un discours et pour analyser les motifs linguistiques extraits par notre approche artificielle par rapport aux techniques de phraséologie standard

Linguistic processes do not beat visuo-motor constraints, but they modulate where the eyes move regardless of word boundaries: Evidence against top-down word-based eye-movement control during reading

International audienceWhere readers move their eyes, while proceeding forward along lines of text, has long been assumed to be determined in a top-down word-based manner. According to this classical view, readers of alphabetic languages would invariably program their saccades towards the center of peripheral target words, as selected based on the (expected) needs of ongoing (word-identification) processing, and the variability in within-word landing positions would exclusively result from systematic and random errors. Here we put this predominant hypothesis to a strong test by estimating the respective influences of language-related variables (word frequency and word predictability) and lower-level visuo-motor factors (word length and saccadic launch-site distance to the beginning of words) on both word-skipping likelihood and within-word landing positions. Our eye-movement data were collected while forty participants read 316 pairs of sentences, that differed only by one word, the prime; this was either semantically related or unrelated to a following test word of variable frequency and length. We found that low-level visuo-motor variables largely predominated in determining which word would be fixated next, and where in a word the eye would land. In comparison, language-related variables only had tiny influences. Yet, linguistic variables affected both the likelihood of word skipping and within-word initial landing positions, all depending on the words’ length and how far on average the eye landed from the word boundaries, but pending the word could benefit from peripheral preview. These findings provide a strong case against the predominant word-based account of eye-movement guidance during reading, by showing that saccades are primarily driven by low-level visuo-motor processes, regardless of word boundaries, while being overall subject to subtle, one-off, language-based modulations. Our results also suggest that overall distributions of saccades’ landing positions, instead of truncated within-word landing-site distributions, should be used for a better understanding of eye-movement guidance during reading

Pro- and anti-inflammatory responses of peripheral blood mononuclear cells induced by Staphylococcus aureus and Pseudomonas aeruginosa phages

The ability of bacteriophages to kill bacteria is well known, as is their potential use as alternatives to antibiotics. As such, bacteriophages reach high doses locally through infection of their bacterial host in the human body. In this study we assessed the gene expression profile of peripheral blood monocytes from six donors for twelve immunity-related genes (i.e. CD14, CXCL1, CXCL5, IL1A, IL1B, IL1RN, IL6, IL10, LYZ, SOCS3, TGFBI and TNFA) induced by Staphylococcus aureus phage ISP and four Pseudomonas aeruginosa phages (i.e. PNM, LUZ19, 14- 1 and GE-vB_Pae-Kakheti25). The phages were able to induce clear and reproducible immune responses. Moreover, the overall immune response was very comparable for all five phages: down-regulation of LYZ and TGFBI, and up-regulation of CXCL1, CXCL5, IL1A, IL1B, IL1RN, IL6, SOCS3 and TNFA. The observed immune response was shown to be endotoxinin-dependent and predominantly anti-inflammatory. Addition of endotoxins to the highly purified phages did not cause an immune response comparable to the one induced by the (endotoxin containing) phage lysate. In addition, the use of an intermediate level of endotoxins tipped the immune response to a more anti-inflammatory response, i.e. up-regulation of IL1RN and a strongly reduced expression of CXCL1 and CXCL5

Influence of the mode of reproduction on dispersal evolution during species invasion

We consider a reaction-diffusion-reproduction equation, modeling a population which is spatially heterogeneous. The dispersion of each individuals is influenced by its phenotype. In the literature, the asymptotic propagation speed of an asexual population has already been rigorously determined. In this paper we focus on the difference between the asexual reproduction case, and the sexual reproduction case, involving a non-local term modeling the reproduction. This comparison leads to a different invasion speed according to the reproduction. After a formal analysis of both cases, leading to a heuristic of the asymptotic behaviour of the invasion fronts, we give some numerical evidence that the acceleration rate of the spatial spreading of a sexual population is slower than the acceleration rate of an asexual one. The main difficulty to get sharper results on a transient comes from the non-local sexual reproduction term

14-3-3 Proteins Regulate a Cell-Intrinsic Switch from Sonic Hedgehog-Mediated Commissural Axon Attraction to Repulsion after Midline Crossing

SummaryAxons must switch responsiveness to guidance cues during development for correct pathfinding. Sonic Hedgehog (Shh) attracts spinal cord commissural axons ventrally toward the floorplate. We show that after crossing the floorplate, commissural axons switch their response to Shh from attraction to repulsion, so that they are repelled anteriorly by a posterior-high/anterior-low Shh gradient along the longitudinal axis. This switch is recapitulated in vitro with dissociated commissural neurons as they age, indicating that the switch is intrinsic and time dependent. 14-3-3 protein inhibition converted Shh-mediated repulsion of aged dissociated neurons to attraction and prevented the correct anterior turn of postcrossing commissural axons in vivo, an effect mediated through PKA. Conversely, overexpression of 14-3-3 proteins was sufficient to drive the switch from Shh-mediated attraction to repulsion both in vitro and in vivo. Therefore, we identify a 14-3-3 protein-dependent mechanism for a cell-intrinsic temporal switch in the polarity of axon turning responses