FGF signaling controls somite boundary position and regulates segmentation clock control of spatiotemporal Hox gene activation

AbstractVertebrate segmentation requires a molecular oscillator, the segmentation clock, acting in presomitic mesoderm (PSM) cells to set the pace at which segmental boundaries are laid down. However, the signals that position each boundary remain unclear. Here, we report that FGF8 which is expressed in the posterior PSM, generates a moving wavefront at which level both segment boundary position and axial identity become determined. Furthermore, by manipulating boundary position in the chick embryo, we show that Hox gene expression is maintained in the appropriately numbered somite rather than at an absolute axial position. These results implicate FGF8 in ensuring tight coordination of the segmentation process and spatiotemporal Hox gene activation

Afasiaren azterketa hizkuntza ezberdinetan neurozientzia kognitiboaren ikuspegitik (Aphasia research in different languages from the perspective of cognitive neuroscience)

Jasoa: 2016-05-14The goal of this paper is to define aphasia and aphasiology from the perspective of cognitive neuroscience. In addition, it emphasizes the need to study aphasia in different languages for a better understanding of brain and language relationships. For this purpose, I take the example of agrammatic verb processing assessment. Finally, I mention some future lines of research regarding Basque aphasiology and the assessment of multilingual people with aphasia

Mathematical models for somite formation

Somitogenesis is the process of division of the anterior–posterior vertebrate embryonic axis into similar morphological units known as somites. These segments generate the prepattern which guides formation of the vertebrae, ribs and other associated features of the body trunk. In this work, we review and discuss a series of mathematical models which account for different stages of somite formation. We begin by presenting current experimental information and mechanisms explaining somite formation, highlighting features which will be included in the models. For each model we outline the mathematical basis, show results of numerical simulations, discuss their successes and shortcomings and avenues for future exploration. We conclude with a brief discussion of the state of modeling in the field and current challenges which need to be overcome in order to further our understanding in this area

Mathematical models for somite formation

Somitogenesis is the process of division of the anterior–posterior vertebrate embryonic axis into similar morphological units known as somites. These segments generate the prepattern which guides formation of the vertebrae, ribs and other associated features of the body trunk. In this work, we review and discuss a series of mathematical models which account for different stages of somite formation. We begin by presenting current experimental information and mechanisms explaining somite formation, highlighting features which will be included in the models. For each model we outline the mathematical basis, show results of numerical simulations, discuss their successes and shortcomings and avenues for future exploration. We conclude with a brief discussion of the state of modeling in the field and current challenges which need to be overcome in order to further our understanding in this area

Experimental methods to study atypical language development

In this chapter we present current issues on experimental methods in the study of atypical language development with a focus on developmental language disorders (DLD). We first present a short history of terminology surrounding DLD and follow this with a discussion of critical topics related to DLD assessment including cross-linguistic research, multilingualism, persisting disorders in teenagers, age-differences (pre-school, school age, adolescence, and adults) in manifestations and domains studied, language comprehension versus production, and cognitive assessment. We also bring focus to the question of matching control groups in the study of atypical language development. We present the most common methods used in the investigation of language impairments from the behavioural and neurocognitive perspectives. We provide an overview of the issues related to establishing equivalence between groups with and without language impairments. We conclude with recommendations for practice and future directions in the study of atypical language development

No “Self” Advantage for Audiovisual Speech Aftereffects

Published: 22 March 2019.Although the default state of the world is that we see and hear other people talking, there is evidence that seeing and hearing ourselves rather than someone else may lead to visual (i.e., lip-read) or auditory “self” advantages. We assessed whether there is a “self” advantage for phonetic recalibration (a lip-read driven cross-modal learning effect) and selective adaptation (a contrastive effect in the opposite direction of recalibration). We observed both aftereffects as well as an on-line effect of lip-read information on auditory perception (i.e., immediate capture), but there was no evidence for a “self” advantage in any of the tasks (as additionally supported by Bayesian statistics). These findings strengthen the emerging notion that recalibration reflects a general learning mechanism, and bolster the argument that adaptation depends on rather low-level auditory/acoustic features of the speech signal.This work was supported by the Severo Ochoa program grant SEV-2015-049 awarded to the BCBL. MB and MP were supported by the Spanish Ministry of Economy and Competitiveness (MINECO, grant PSI2014-51874-P), and MB was also supported by the Netherlands Organization for Scientific Research (NWO, VENI grant 275-89-027)

A clock and wavefront mechanism for somite formation

Somitogenesis, the sequential formation of a periodic pattern along the antero-posterior axis of vertebrate embryos, is one of the most obvious examples of the segmental patterning processes that take place during embryogenesis and also one of the major unresolved events in developmental biology. In this article, we develop a mathematical formulation of a new version of the Clock and Wavefront model proposed by Pourquié and co-workers (Dubrulle, J., McGrew, M.J., Pourquié, O., 2001. FGF signalling controls somite boundary position and regulates segmentation clock control of spatiotemporal Hox gene activation. Cell 106, 219–232). Dynamic expression of FGF8 in the presomitic mesoderm constitutes the wavefront of determination which sweeps along the body axis interacting as it moves with the segmentation clock to gate cells into somites. We also show that the model can mimic the anomalies formed when progression of the wavefront is disturbed and make some experimental predictions that can be used to test the hypotheses underlying the model

No “Self” Advantage for Audiovisual Speech Aftereffects

Although the default state of the world is that we see and hear other people talking, there is evidence that seeing and hearing ourselves rather than someone else may lead to visual (i.e., lip-read) or auditory “self” advantages. We assessed whether there is a “self” advantage for phonetic recalibration (a lip-read driven cross-modal learning effect) and selective adaptation (a contrastive effect in the opposite direction of recalibration). We observed both aftereffects as well as an on-line effect of lip-read information on auditory perception (i.e., immediate capture), but there was no evidence for a “self” advantage in any of the tasks (as additionally supported by Bayesian statistics). These findings strengthen the emerging notion that recalibration reflects a general learning mechanism, and bolster the argument that adaptation depends on rather low-level auditory/acoustic features of the speech signal

Basque-Spanish bilingual children’s expressive and receptive grammatical abilities

Published online: 26 Nov 2018Expressive-receptive gaps in lexical abilities have been documented for bilingual children, but few studies have investigated whether a similar gap is observed at the grammatical level. The current study assessed grammatical abilities through sentence production and comprehension tasks in both languages in 17 Basque-Spanish simultaneous bilingual 6- through 9-year-olds (both languages acquired before three years of age). The children scored lower in Basque than Spanish for sentence production, but no significant differences were found for sentence comprehension. While an expressive-receptive gap was found for both languages, this gap was larger in Basque than in Spanish. Object-verb agreement errors were especially prevalent in Basque production, possibly because verbs in Spanish only agree with the subject. These results demonstrate that expressive-receptive gaps are also observed in bilingual children’s grammatical abilities and may vary depending on the structural similarity between the two languages.The authors acknowledge financial support from the Spanish Ministry of Economy and Competitiveness, through the Severo Ochoa Programme for Centres/Units of Excellence in R&D (SEV-2015-490)