Role of LRR-RLKS in stress response and developmental processes through systematic K.O. analysis in rice

The function of a small number of Leucine-Rich Repeat Receptor-Like Kinase (LRR-RLK) genes has been studied, mostly in Arabidopsis thaliana. They are involved in several important biological processes, including development, resistance/defence and adaptation to biotic and abiotic stresses. We are interested in deciphering the function of these genes in rice. In this aim, we decided to take advantage of the availability of T-DNA and Tos17 insertion mutant libraries of rice cv. Nipponbare to start a systematic screen of knock-out mutants of these genes. The rice genome contains ~320 LRRRLK genes. Our search in international collections of insertion mutant lines which are catalogued by Flanking Sequence Tag (FST) information from most of the rice insertional mutagenesis projects around the world revealed that 238 insertional mutant lines are available for the 323 genes. Phenotypical evaluation of homozygous mutants is performed under various biotic and abiotic stresses and mutant plants are observed for phenotypes at several stages of growth, from seedlings in Petri dishes to flowering and grain development stages in the greenhouse. Thus, with this project, we aim first to decipher and explore new genes involved in defence and developmental responses to stresses. Second, our analysis will be of great benefit to provide potential targets for cereal improvement, notably in the breeding of drought-tolerant and pathogen-resistant crops. This project is supported by grant #ANR-08-GENM-021 from Agence Nationale de la recherche (ANR), France. (Résumé d'auteur

The influences and outcomes of phonological awareness: a study of MA, PA and auditory processing in pre-readers with a family risk of dyslexia

The direct influence of phonological awareness (PA) on reading outcomes has been widely demonstrated, yet PA may also exert indirect influence on reading outcomes through other cognitive variables such as morphological awareness (MA). However, PA's own development is dependent and influenced by many extraneous variables such as auditory processing, which could ultimately impact reading outcomes. In a group of pre-reading children with a family risk of dyslexia and low-risk controls, this study sets out to answer questions surrounding PA's relationship at various grain sizes (syllable, onset/rime and phoneme) with measures of auditory processing (frequency modulation (FM) and an amplitude rise-time task (RT)) and MA, independent of reading experience. Group analysis revealed significant differences between high- and low-risk children on measures of MA, and PA at all grain sizes, while a trend for lower RT thresholds of high-risk children was found compared with controls. Correlational analysis demonstrated that MA is related to the composite PA score and syllable awareness. Group differences on MA and PA were re-examined including PA and MA, respectively, as control variables. Results exposed PA as a relevant component of MA, independent of reading experience

The Sound Sensation of Apical Electric Stimulation in Cochlear Implant Recipients with Contralateral Residual Hearing

BACKGROUND: Studies using vocoders as acoustic simulators of cochlear implants have generally focused on simulation of speech understanding, gender recognition, or music appreciation. The aim of the present experiment was to study the auditory sensation perceived by cochlear implant (CI) recipients with steady electrical stimulation on the most-apical electrode. METHODOLOGY/PRINCIPAL FINDINGS: Five unilateral CI users with contralateral residual hearing were asked to vary the parameters of an acoustic signal played to the non-implanted ear, in order to match its sensation to that of the electric stimulus. They also provided a rating of similarity between each acoustic sound they selected and the electric stimulus. On average across subjects, the sound rated as most similar was a complex signal with a concentration of energy around 523 Hz. This sound was inharmonic in 3 out of 5 subjects with a moderate, progressive increase in the spacing between the frequency components. CONCLUSIONS/SIGNIFICANCE: For these subjects, the sound sensation created by steady electric stimulation on the most-apical electrode was neither a white noise nor a pure tone, but a complex signal with a progressive increase in the spacing between the frequency components in 3 out of 5 subjects. Knowing whether the inharmonic nature of the sound was related to the fact that the non-implanted ear was impaired has to be explored in single-sided deafened patients with a contralateral CI. These results may be used in the future to better understand peripheral and central auditory processing in relation to cochlear implants

Higher Sensitivity of Human Auditory Nerve Fibers to Positive Electrical Currents

Most contemporary cochlear implants (CIs) stimulate the auditory nerve with trains of amplitude-modulated, symmetric biphasic pulses. Although both polarities of a pulse can depolarize the nerve fibers and generate action potentials, it remains unknown which of the two (positive or negative) phases has the stronger effect. Understanding the effects of pulse polarity will help to optimize the stimulation protocols and to deliver the most relevant information to the implant listeners. Animal experiments have shown that cathodic (negative) current flows are more effective than anodic (positive) ones in eliciting neural responses, and this finding has motivated the development of novel speech-processing algorithms. In this study, we show electrophysiologically and psychophysically that the human auditory system exhibits the opposite pattern, being more sensitive to anodic stimulation. We measured electrically evoked compound action potentials in CI listeners for phase-separated pulses, allowing us to tease out the responses to each of the two opposite-polarity phases. At an equal stimulus level, the anodic phase yielded the larger response. Furthermore, a measure of psychophysical masking patterns revealed that this polarity difference was still present at higher levels of the auditory system and was therefore not solely due to antidromic propagation of the neural response. This finding may relate to a particular orientation of the nerve fibers relative to the electrode or to a substantial degeneration and demyelination of the peripheral processes. Potential applications to improve CI speech-processing strategies are discussed

Pitch Comparisons between Electrical Stimulation of a Cochlear Implant and Acoustic Stimuli Presented to a Normal-hearing Contralateral Ear

Four cochlear implant users, having normal hearing in the unimplanted ear, compared the pitches of electrical and acoustic stimuli presented to the two ears. Comparisons were between 1,031-pps pulse trains and pure tones or between 12 and 25-pps electric pulse trains and bandpass-filtered acoustic pulse trains of the same rate. Three methods—pitch adjustment, constant stimuli, and interleaved adaptive procedures—were used. For all methods, we showed that the results can be strongly influenced by non-sensory biases arising from the range of acoustic stimuli presented, and proposed a series of checks that should be made to alert the experimenter to those biases. We then showed that the results of comparisons that survived these checks do not deviate consistently from the predictions of a widely-used cochlear frequency-to-place formula or of a computational cochlear model. We also demonstrate that substantial range effects occur with other widely used experimental methods, even for normal-hearing listeners

Perceptual Discrimination of Speaking Style Under Cochlear Implant Simulation

Contains fulltext : 201550pub.pdf (publisher's version ) (Open Access)14 p

When the Deaf Listen to Music - Pitch Perception in Cochlear Implants (Als doven naar muziek luisteren - Toonhoogtewaarneming met een cochleair implantaat)

Cochleaire implantaten (CI) zijn een type hoorapparaat dat toelaat om do ve mensen opnieuw te laten horen door middel van rechtstreekse elektrisc he stimulatie van de gehoorzenuw. Hoewel een CI toelaat om spraak te ver staan in een stille omgeving, is de toonhoogtewaarneming bij geïmplantee rde personen ongeveer 50 maal slechter dan bij normaalhorende (NH) perso nen. Toonhoogte is echter belangrijk voor intonatie, muziek, spraakverst aan bij tonale talen, en voor het onderscheiden van meerdere gelijktijdi ge geluidsbronnen. Het hoofddoel van dit proefschrift is het verbeteren van de toonhoogtewaarneming door CI patiënten. CI patiënten gebruiken twee basismechanismen voor toonhoogtewaarneming: plaats-afhankelijke toonhoogte en temporele toonhoogte. Onze resultaten tonen aan dat de plaatsafhankelijke toonhoogte (of plaatstoonhoogte) bep aald wordt door het zwaartepunt van het elektrisch stimulatiepatroon lan gsheen de cochlea. De steilheid van de flanken van het stimulatiepatroon bepaalt de gevoeligheid van de patiënt voor veranderingen in plaatstoon hoogte. We tonen ook aan dat de efficiëntie van het temporele toonhoogte mechanisme vergroot bij grotere modulatiediepte en wanneer de verschille nde kanalen synchroon gemoduleerd zijn. Onze resultaten tonen verder aan dat de twee toonhoogtemechanismen kunnen gecombineerd kunnen worden in een globale toonhoogtewaarneming die gebruikt wordt voor de discriminati e van de fundamentele frequentie (F0). De toonhoogte die NH personen waa rnemen komt overeen met de fundamentele frequentie (F0) van het geluid. De bijdrage van het plaatstoonhoogte -mechanisme is echter zwak omwille van de interactie van het mechanisme met de omhullende van het spectrum en omwille van de vrij vlakke flanken van het excitatiepatroon door het uitsmeren van de elektrische stroom in de cochlea. Het temporele toonho ogtemechanisme draagt het meest efficiënt bij tot F0-discriminatie maar is beperkt door de meer centrale neurale verwerking. Hoewel we aantonen dat de doeltreffendheid voor F0-discriminatie van ofwel de plaats-toonho ogte ofwel de temporele toonhoogte kan verbeterd worden d.m.v. specifiek e filterbanken, tonen we ook aan dat het niet mogelijk is met de huidige signaalverwerkingsschemas deze beide mechanismen optimaal te benutten. Daarom is in dit proefschrift een nieuw geluidsverwerkingsschema ontwikk eld dat ontworpen is om de toonhoogtewaarneming te optimaliseren. Dankzi j dit nieuwe schema kunnen CI patiënten driemaal kleinere toonhoogtevers chillen onderscheiden en herkennen ze meer melodieën.05/05nrpages: 241status: publishe

Un îlot-jardin à l’entrée du campus

— Regrouper dans un vaste complexe paysagé en façade sur le boulevard Schweitzer l’ensemble des activités de formation et de recherche rattachées au domaine agro-alimentaire. — Doter cet ensemble d’une forte identité paysagère, à partir d’un réseau d’allées et de cheminements convergeant vers un jardin intérieur, et donner une bonne lisibilité de l’ensemble en articulant les volumes bâtis. — Le projet d’extension du pôle agro-alimentaire vient se greffer à l’équipement de l’ISTAB existant. Pa..