Novas Pragas Agrícolas na Ilha de São Nicolau - Cabo Verde - Tuta absoluta (Meyrick) (Lep - Gelechiidae) e Bactrocera invadens (Drew, Tsuruta & White) (Dipt - Tephritidae)

Em algumas das ilhas do Arquipélago de Cabo Verde entraram, nos últimos dois anos, espécies invasoras que constituem pragas de culturas agrícolas e que têm apresentado elevada repercussão económica. Entre elas contam-se a traça do tomateiro, Tuta absoluta (Meyrick) (Lepidoptera: Gelechidae) e Bactrocera invadens (Drew, Tsuruta & White) (Diptera: Tephritidae). Com o objectivo de avaliar a presença destas pragas na ilha de São Nicolau, foram instaladas armadilhas com atractivos em quatro zonas com bananeiras (Ribeira Prata, Fajã, Maiama e Campo de Preguiça) para a monitorização da mosca da fruta. Foram também instaladas ensaios em seis parcelas de tomateiro para a comparação de estratégias de protecção contra T. absoluta, armadilha com feromona sexual para captura em massa em conjunto com Bacillus thuringiensis e tratamento com deltametrina. Das quatro zonas monitorizadas, B. invadens só foi encontrada no Vale da Fajã. No que diz respeito a T. absoluta, fez-se a comparação entre a população presente em três estratos do tomateiro e não se encontraram diferenças significativas. As estratégias de protecção contra T. absoluta também não diferiram significativamente no que se refere ao número de minas nas folhas e frutos furados. Nesidiocoris tenuis foi identificado como inimigo natural de T. absoluta presente na ilha.

Les adénocarcinomes kystiques de la glande lacrymale [Cystic adenocarcinomas of the lacrymal gland]

Adenoid cystic carcinoma of the lacrimal gland. BACKGROUND: Adenoid cystic carcinoma is the most frequent epithelial tumour of the lacrimal gland. It represents 1.6 % of the orbital tumours. The aim of this study is to present a series of such patients who were followed up in our clinic and to discuss their clinical management in order to achieve a better life prognosis. MATERIALS AND METHODS: The cases we followed up in our department were presented, the treatment modalities were discussed, and conclusions were drawn. RESULTS: Six patients with this pathology were examined, 3 men and 3 women, aged 31 to 69 years. A large excision was performed in 5 patients (exenteration alone or extended exenteration with complementary radiotherapy) and in 1 patient with excision of the tumour followed by radiotherapy. One patient died due to carcinoma six years after the first surgery. The median follow-up period of our cases is 25 months. CONCLUSION: Adenoid cystic carcinoma of the lacrimal gland is a malignant tumour with a reserved prognosis. Various treatments were proposed to improve the mortality rate of the disease. At present radical surgery with or without complementary therapy seems to give the best chances of healing, at least with short or mid-term follow-up.

Outcome and patterns of failure in testicular lymphoma: a multicenter Rare Cancer Network study.

PURPOSE: To assess the outcome and patterns of failure in patients with testicular lymphoma treated by chemotherapy (CT) and/or radiation therapy (RT). METHODS AND MATERIALS: Data from a series of 36 adult patients with Ann Arbor Stage I (n = 21), II (n = 9), III (n = 3), or IV (n = 3) primary testicular lymphoma, consecutively treated between 1980 and 1999, were collected in a retrospective multicenter study by the Rare Cancer Network. Median age was 64 years (range: 21-91 years). Full staging workup (chest X-ray, testicular ultrasound, abdominal ultrasound, and/or thoracoabdominal computer tomography, bone marrow assessment, full blood count, lactate dehydrogenase, and cerebrospinal fluid evaluation) was completed in 18 (50%) patients. All but one patient underwent orchidectomy, and spermatic cord infiltration was found in 9 patients. Most patients (n = 29) had CT, consisting in most cases of cyclophosphamide, doxorubicin, vincristine, and prednisolone (CHOP) with (n = 17) or without intrathecal CT. External RT was delivered to scrotum alone (n = 12) or testicular, iliac, and para-aortic regions (n = 8). The median RT dose was 31 Gy (range: 20-44 Gy) in a median of 17 fractions (10-24), using a median of 1.8 Gy (range: 1.5-2.5 Gy) per fraction. The median follow-up period was 42 months (range: 6-138 months). RESULTS: After a median period of 11 months (range: 1-76 months), 14 patients presented lymphoma progression, mostly in the central nervous system (CNS) (n = 8). Among the 17 patients who received intrathecal CT, 4 had a CNS relapse (p = NS). No testicular, iliac, or para-aortic relapse was observed in patients receiving RT to these regions. The 5-year overall, lymphoma-specific, and disease-free survival was 47%, 66%, and 43%, respectively. In univariate analyses, statistically significant factors favorably influencing the outcome were early-stage and combined modality treatment. Neither RT technique nor total dose influenced the outcome. Multivariate analysis revealed that the most favorable independent factors predicting the outcome were younger age, early-stage disease, and combined modality treatment. CONCLUSIONS: In this multicenter retrospective study, CNS was found to be the principal site of relapse, and no extra-CNS lymphoma progression was observed in the irradiated volumes. More effective CNS prophylaxis, including combined modalities, should be prospectively explored in this uncommon site of extranodal lymphoma.

Exercice physique et artériopathie oblitérante des membres inférieurs [Physical activity and peripheral arterial obstructive disease]

Intermittent claudication (IC) is the most common clinical manifestation of atherosclerotic peripheral arterial disease. Exercise training plays a major role in treating patients with IC. Regular exercise increases functional walking capacity, reduces cardiovascular mortality and improves quality of life. This seems to be achieved by: favorable effect on cardiovascular risk factors, anti-inflammatory effect, increased collateral blood flux, improved rheology profile, endothelial function, fibrinolysis, and muscular metabolism. However, exact mechanisms underlying beneficial effect of exercise remain largely unknown. Exercise modalities will be discussed in this article.

Dosimetric aspects of a national survey of diagnostic and interventional radiology in Switzerland.

The effective dose delivered to the patient was determined, by modeling, for 257 types of examinations covering the different modalities of diagnostic and interventional radiology. The basic operational dosimetric quantities considered were obtained from the parameters of the examinations on the basis of dosimetric models. These models required a precise characterization of each examination. The operational dosimetric quantities were converted into doses to organs and effective doses using appropriate conversion factors. The determination of the collective effective dose to the Swiss population requires a number of corrections to account for the variability of several parameters: sensitivity of the detection system, age, gender, and build of the patient. The use of various dosimetric models is illustrated in this paper for a limited number of examination types covering the different radiological modalities, for which the established typical effective doses are given. With regard to individual doses, the study indicated that the average effective doses per type of examination can be classified into three levels: (a) the weakly irradiating examinations (less than 0.1 mSv), which represent 78% of the examinations and 4% of the collective dose, (b) the moderately irradiating examinations (between 0.1 mSv and 10 mSv), which represent 21% of the examinations and 72% of the collective dose, (c) the strongly irradiating examinations (more than 10 mSv), which represent 1% of the examinations and 24% of the collective dose.

Lire l'oral : pour une typologie linguistique des représentations écrites de l'oralité (le cas du français)

Cette thèse propose de passer en revue les modalités de la représentation écrite de l'oralité en français. La pratique littéraire constitue le matériau et l'horizon de la théorisation. La problématique - comment l'écrit représente-t-il l'oral ? - est d'abord située et reformulée dans le cadre de la linguistique de la parole (I). Les rapports entre oralité et scripturalité sont ensuite étudiés sous trois angles. L'angle biotechnologique compare la matérialité et l'affordance des signaux graphiques et des signaux acoustiques (II 1). L'examen sémiotique reconnaît dans le français écrit un système dit phonographique dont la fonction est de représenter l'expression des signes du français oral. Sont analysées alors les relations entre les systèmes de signes impliqués, la diversité des actualisations possibles du système phonographique (effets d'écoute), ainsi que diverses sémiotiques analogiques (II 2). On étudie ensuite le rôle de la prosodie dans la lecture. La position adoptée est la suivante : bien qu'elle soit facultative dans l'activité de lecture, la prosodie est spécialement sollicitée par des écrits qu'on peut caractériser linguistiquement. L'interprétation prosodique apporte à ces écrits un surcroît de signification en même temps qu'il produit un mode spécifique de représentation de l'oral appelé effet prosodique (II 3). L'angle sémantique est esquissé finalement : il conduit à dégager deux modalités de représentation supplémentaire. Pour la première, l'oral se situe sur le plan sémantico-référentiel de l'expression écrite (écrire à propos d'oral) ; pour la seconde, l'oral est un extérieur discursif modalisant le dire écrit : l'écrit est reconnu comme énoncé à la manière de l'oral (effet de style oral). - This PhD thesis attempts to review the modalities of orality in written representation. Literary writings act as the material for theorization. First of all, the thesis statement - how does writing represent oral - is situated and then, reformulated within the frame of linguistique de la parole (the linguistic field of speech) (I). The connections between orality and writing are then studied under three angles. The biotechnological angle compares the materiality and the affordance of graphic signs and acoustic signals (II 1). A semiotic examination acknowledges, in French, a phonographical system whose function is to represent the expression of French oral signs. Thus, the relationships between the systems of implicated signs, the diversity of possible actualisations of the phonographic system (voice effects), as well as various analogical semiotics are analysed (II 2). Furthermore, the role of prosody is studied within reading. The stand taken is the following : even though it is optional during a reading activity, prosody is especially sought-after by linguistically characterised writings. The prosodie interpretation brings to these writings a surge of signification while producing a specific mode of oral representation called the prosodie effects (II 3). The semantic angle is finally drawn : it leads to two additional modalities of representation. For the first part, speech is located on the semantic and referential plan of the written expression (writing about speech); as for the second part, spoken language is a discursive exteriority : writing is recognised as an oral-like utterance {oral-like effect).

Psychothérapie psychodynamique brève de la dépression pour patients hospitalisés

L'objectif de cet article est de proposer une réflexion sur l'opportunité que représente l'hospitalisation de s'intéresser à la dépression en tant que travail de métabolisation psychique d'une expérience subjective significative, ou de son échec. Cet article présente les principales modalités organisatrices de la psychothérapie en 12 séances (à raison de 3 séances hebdomadaires) que nous avons mise en place pour les patients hospitalisés souffrant d'un épisode dépressif unipolaire. Lors de celle-ci, le psychothérapeute situe son intervention sur la base de quatre organisateurs : la thématique conflictuelle que révèlent l'hospitalisation et la crise, la structure de personnalité du patient, la brièveté de la psychothérapie et la psychopathologie du symptôme. Ces organisateurs vont encadrer le processus et lui conférer son originalité. Un récit clinique illustre comment cette psychothérapie, même brève, peut remettre en mouvement une situation par la constitution (la reprise) d'une historicité psychique de l'épisode dépressif. Notre expérience clinique montre qu'un tel dispositif délimite clairement un espace permettant une écoute psychanalytique authentique des patients souffrant de dépression grave. The aim of this article is to propose a reflection on the opportunity that hospitalization can represent as a way to think of depression in terms of psychic metabilisation of a significant subjective experience, or its feature. The article presents the main modalities through which this approach is organized for hospitalized unipolar patients in a phase of depression. It comprises 12 sessions (3 per week), The psychotherapit's intervention is organized around 4 basic themes : the conflict revealed in the crisis surrounding hospitalization, personality structure, briefness of psychotherapy and the psychopathology of the symptom. These organisors are the framework that lend this process its originality. A clinical vignette illustrates how this psychotherapy, though brief, is able to remobilize a situation through retrieving the psychical historicity of the depressed episode. Our clinical experience shows that this dispositive is a clearly destined space for lending an authentic psychoanalytic ear.

Intensity modulated radiation therapy or stereotactic fractionated radiotherapy for infratentorial ependymoma in children: a multicentric study.

This study was to evaluate the treatment dosimetry, efficacy and toxicity of intensity modulated radiation therapy (IMRT) and fractionated stereotactic radiotherapy (FSRT) in the management of infratentorial ependymoma. Between 1999 and 2007, seven children (median age, 3.1 years) with infratentorial ependymoma were planned with either IMRT (3 patients) or SFRT (4 patients), the latter after conventional posterior fossa irradiation. Two children underwent gross total resection. Median prescribed dose was 59.4 Gy (range, 55.8-60). The median follow-up for surviving patients was 4.8 years (range, 1.3-8). IMRT (median dose, 59.4 Gy) and FSRT (median dose, 55.8 Gy) achieved similar optimal target coverage. Percentages of maximum doses delivered to the cochleae (59.5 vs 85.0% Gy; P = 0.05) were significantly inferior with IMRT, when compared to FSRT planning. Percentages of maximum doses administered to the pituitary gland (38.2 vs 20.1%; P = 0.05) and optic chiasm (38.1 vs 14.1%; P = 0.001) were, however, significantly higher with IMRT, when compared to FSRT planning. No recurrences were observed at the last follow-up. The estimated 3-year progression-free survival and overall survival were 87.5 and 100%, respectively. No grade >1 acute toxicity was observed. Two patients presented late adverse events (grade 2 hypoacousia) during follow-up, without cognitive impairment. IMRT or FSRT for infratentorial ependymomas is effective and associated with a tolerable toxicity level. Both treatment techniques were able to capitalize their intrinsic conformal ability to deliver high-dose radiation. Larger series of patients treated with these two modalities will be necessary to more fully evaluate these delivery techniques.

Model-based Segmentation and Fusion of 3D Computed Tomography and 3D Ultrasound of the Eye for Radiotherapy Planning

Computed Tomography (CT) represents the standard imaging modality for tumor volume delineation for radiotherapy treatment planning of retinoblastoma despite some inherent limitations. CT scan is very useful in providing information on physical density for dose calculation and morphological volumetric information but presents a low sensitivity in assessing the tumor viability. On the other hand, 3D ultrasound (US) allows a highly accurate definition of the tumor volume thanks to its high spatial resolution but it is not currently integrated in the treatment planning but used only for diagnosis and follow-up. Our ultimate goal is an automatic segmentation of gross tumor volume (GTV) in the 3D US, the segmentation of the organs at risk (OAR) in the CT and the registration of both modalities. In this paper, we present some preliminary results in this direction. We present 3D active contour-based segmentation of the eye ball and the lens in CT images; the presented approach incorporates the prior knowledge of the anatomy by using a 3D geometrical eye model. The automated segmentation results are validated by comparing with manual segmentations. Then, we present two approaches for the fusion of 3D CT and US images: (i) landmark-based transformation, and (ii) object-based transformation that makes use of eye ball contour information on CT and US images.

Development of the Crohn's disease digestive damage score, the Lémann score.

Crohn's disease (CD) is a chronic progressive destructive disease. Currently available instruments measure disease activity at a specific point in time. An instrument to measure cumulative structural damage to the bowel, which may predict long-term disability, is needed. The aim of this article is to outline the methods to develop an instrument that can measure cumulative bowel damage. The project is being conducted by the International Program to develop New Indexes in Crohn's disease (IPNIC) group. This instrument, called the Crohn's Disease Digestive Damage Score (the Lémann score), should take into account damage location, severity, extent, progression, and reversibility, as measured by diagnostic imaging modalities and the history of surgical resection. It should not be "diagnostic modality driven": for each lesion and location, a modality appropriate for the anatomic site (for example: computed tomography or magnetic resonance imaging enterography, and colonoscopy) will be used. A total of 24 centers from 15 countries will be involved in a cross-sectional study, which will include up to 240 patients with stratification according to disease location and duration. At least 120 additional patients will be included in the study to validate the score. The Lémann score is expected to be able to portray a patient's disease course on a double-axis graph, with time as the x-axis, bowel damage severity as the y-axis, and the slope of the line connecting data points as a measure of disease progression. This instrument could be used to assess the effect of various medical therapies on the progression of bowel damage. (Inflamm Bowel Dis 2011).

Primary mucosa-associated lymphoid tissue lymphoma of the salivary glands: a multicenter Rare Cancer Network study.

Purpose: Involvement of salivary glands with mucosa-associated lymphoid tissue (MALT) lymphoma is rare. This retrospective study was performed to assess the clinical profile, treatment outcome, and prognostic factors of MALT lymphoma of the salivary glands.Methods and Materials: Thirteen member centers of the Rare Cancer Network from 10 countries participated, providing data on 63 patients. The median age was 58 years; 47 patients were female and 16 were male. The parotid glands were involved in 49 cases, submandibular in 15, and minor glands in 3. Multiple glands were involved in 9 patients. Staging was as follows: IE in 34, IIE in 12, IIIE in 2, and IV in 15 patients.Results: Surgery (S) alone was performed in 9, radiotherapy (RI) alone in 8, and chemotherapy (CT) alone in 4 patients. Forty-one patients received combined modality treatment (S + RT in 23, S + CT in 8, RT + CT in 4, and all three modalities in 6 patients). No active treatment was given in one case. After initial treatment there was no tumor in 57 patients and residual tumor in 5. Tumor progression was observed in 23 (36.5%) (local in 1, other salivary glands in 10, lymph nodes in 11, and elsewhere in 6). Five patients died of disease progression and the other 5 of other causes. The 5-year disease-free survival, disease-specific survival, and overall survival were 54.4%, 93.2%, and 81.7%, respectively. Factors influencing disease-free survival were use of RI, stage, and residual tumor (p < 0.01). Factors influencing disease-specific survival were stage, recurrence, and residual tumor (p < 0.01).Conclusions: To our knowledge, this report represents the largest series of MALT lymphomas of the salivary glands published to date. This disease may involve all salivary glands either initially or subsequently in 30% of patients. Recurrences may occur in up to 35% of patients at 5 years; however, survival is not affected. Radiotherapy is the only treatment modality that improves disease-free survival. (C) 2012 Elsevier Inc.

Haemodynamic consequences of changing bicarbonate and calcium concentrations in haemodialysis fluids.

BACKGROUND: In a previous study we demonstrated that mild metabolic alkalosis resulting from standard bicarbonate haemodialysis induces hypotension. In this study, we have further investigated the changes in systemic haemodynamics induced by bicarbonate and calcium, using non-invasive procedures. METHODS: In a randomized controlled trial with a single-blind, crossover design, we sequentially changed the dialysate bicarbonate and calcium concentrations (between 26 and 35 mmol/l for bicarbonate and either 1.25 or 1.50 mmol/l for calcium). Twenty-one patients were enrolled for a total of 756 dialysis sessions. Systemic haemodynamics was evaluated using pulse wave analysers. Bioimpedance and BNP were used to compare the fluid status pattern. RESULTS: The haemodynamic parameters and the pre-dialysis BNP using either a high calcium or bicarbonate concentration were as follows: systolic blood pressure (+5.6 and -4.7 mmHg; P < 0.05 for both), stroke volume (+12.3 and +5.2 ml; P < 0.05 and ns), peripheral resistances (-190 and -171 dyne s cm(-5); P < 0.05 for both), central augmentation index (+1.1% and -2.9%; ns and P < 0.05) and BNP (-5 and -170 ng/l; ns and P < 0.05). The need of staff intervention was similar in all modalities. CONCLUSIONS: Both high bicarbonate and calcium concentrations in the dialysate improve the haemodynamic pattern during dialysis. Bicarbonate reduces arterial stiffness and ameliorates the heart tolerance for volume overload in the interdialytic phase, whereas calcium directly increases stroke volume. The slight hypotensive effect of alkalaemia should motivate a probative reduction of bicarbonate concentration in dialysis fluid for haemodynamic reasons, only in the event of failure of classical tools to prevent intradialytic hypotension.

Failure of the surgical treatment in 115 infected hip arthroplasties-­analysis of a 12-­year prosthetic joint cohort study (1999-­2010)

Background:¦Infection after total or partial hip arthroplasty (HA) leads to significant long-­term morbidity and high healthcare cost. We evaluated reasons for treatment failure of different surgical modalities in a 12-­year prosthetic hip joint infection cohort study.¦Method:¦All patients hospitalized at our institution with infected HA were included either retrospectively (1999-­‐2007) or prospectively¦(2008-­‐2010). HA infection was defined as growth of the same microorganism in ≥2 tissues or synovialfluid culture, visible purulence, sinus tract or acute inflammation on tissue histopathology. Outcome analysis was performed at outpatient visits, followed by contacting patients, their relatives and/or treating physicians afterwards.¦Results:¦During the study period, 117 patients with infected HA were identified. We excluded 2 patients due to missing data. The average age was 69 years (range, 33-­‐102 years); 42% were female. HA was mainly performed for osteoarthritis (n=84), followed by trauma (n=22), necrosis (n=4), dysplasia(n=2), rheumatoid arthritis (n=1), osteosarcoma (n=1) and tuberculosis (n=1). 28 infections occurred early(≤3 months), 25 delayed (3-­‐24 months) and 63 late (≥24 months after surgery). Infected HA were¦treated with (i) two-­‐stage exchange in 59 patients (51%, cure rate: 93%), (ii) one-­‐stage exchange in 5 (4.3%, cure rate: 100%), (iii) debridement with change of mobile parts in 18 (17%, cure rate: 83%), (iv) debridement without change of mobile¦parts in 17 (14%, cure rate : 53% ), (v) Girdlestone in 13 (11%, cure rate: 100%), and (vi) two-­‐stage exchange followed by¦removal in 3 (2.6%). Patients were followed for an average of 3.9 years (range, 0.1 to 9 years), 7 patients died unrelated to the infected HA. 15 patients (13%) needed additional operations, 1 for mechanical reasons(dislocation of spacer) and 14 for persistent infection: 11 treated with debridement and retention (8 without change; and 3 with change of mobile parts) and 3 with two-­‐stage exchange. The average number of surgery was 2.2 (range, 1 to 5). The infection was finally eradicated in all patients, but the functional outcome remained unsatisfactory in 20% (persistent pain or impaired mobility due to spacer or Girdlestone situation).¦Conclusions:¦Non-­‐respect of current treatment concept leads to treatment failure with subsequent operations. Precise analysis of each treatment failure can be used for improving the treatment algorithm leading to better results.

Acknowledgment and health in police officers

The way colleagues and supervisors acknowledge specific contribution and efforts of individuals is crucial for occupational mental health and well being. It contributes to improve the self image of employees and it gives a sense to the activities performed. We carried out a study about occupational health in police officers with a special emphasis on acknowledgment and reward. A questionnaire was sent to 1000 police officers working for a cantonal administration in Switzerland. In total, 695 participants answered the questionnaire. We used the French version of the Langner's questionnaire on psychiatric symptoms to identify cases characterized by potential mental health problems. Multiple choice items (6 modalities ranging from "not at all" to "tremendously") to measure acknowledgment were used. Answers were later dichotomized (low annoyance- high annoyance). Questions we used are: "Do you feel annoyed due to a lack of support and attention from your supervisors?" "Do you feel annoyed because the authorities (politics, judges, etc.) have a low consideration of your occupation?" "Do you feel annoyed due to a low appreciation by the public?" and "Do you feel annoyed due to a lack of acknowledgment by the hierarchy?". The score for psychiatric symptoms was high for 86 police officers for whom health might be at risk. Acknowledgment aspects associated with a high score for psychiatric symptoms are : high annoyance due to a lack of support and attention from supervisors (odds ratio [OR] 3.2, 95% confidence interval [CI] 2.0 to 5.1), high annoyance because authorities seems to have a low consideration for police officers (OR 2.7, 95% CI 1.7 to 4.3), high annoyance due to a low appreciation by the public (OR 1.8, 95% CI 1.2 to 2.9), and high annoyance due to a lack of acknowledgment by the hierarchy (OR 3.0, 95% CI 1.9 to 4.8). Preserving mental health in occupations characterized by high emotional demand is challenging. The results from our study suggest that appropriate acknowledgment might contribute to the prevention of mental health problems. Further research should address a potential causal relation of acknowledgment on mental health.

Multisensory Integration and Perceptual Enhancement

We perceive our environment through multiple sensory channels. Nonetheless, research has traditionally focused on the investigation of sensory processing within single modalities. Thus, investigating how our brain integrates multisensory information is of crucial importance for understanding how organisms cope with a constantly changing and dynamic environment. During my thesis I have investigated how multisensory events impact our perception and brain responses, either when auditory-visual stimuli were presented simultaneously or how multisensory events at one point in time impact later unisensory processing. In "Looming signals reveal synergistic principles of multisensory integration" (Cappe, Thelen et al., 2012) we investigated the neuronal substrates involved in motion detection in depth under multisensory vs. unisensory conditions. We have shown that congruent auditory-visual looming (i.e. approaching) signals are preferentially integrated by the brain. Further, we show that early effects under these conditions are relevant for behavior, effectively speeding up responses to these combined stimulus presentations. In "Electrical neuroimaging of memory discrimination based on single-trial multisensory learning" (Thelen et al., 2012), we investigated the behavioral impact of single encounters with meaningless auditory-visual object parings upon subsequent visual object recognition. In addition to showing that these encounters lead to impaired recognition accuracy upon repeated visual presentations, we have shown that the brain discriminates images as soon as ~100ms post-stimulus onset according to the initial encounter context. In "Single-trial multisensory memories affect later visual and auditory object recognition" (Thelen et al., in review) we have addressed whether auditory object recognition is affected by single-trial multisensory memories, and whether recognition accuracy of sounds was similarly affected by the initial encounter context as visual objects. We found that this is in fact the case. We propose that a common underlying brain network is differentially involved during encoding and retrieval of images and sounds based on our behavioral findings. - Nous percevons l'environnement qui nous entoure à l'aide de plusieurs organes sensoriels. Antérieurement, la recherche sur la perception s'est focalisée sur l'étude des systèmes sensoriels indépendamment les uns des autres. Cependant, l'étude des processus cérébraux qui soutiennent l'intégration de l'information multisensorielle est d'une importance cruciale pour comprendre comment notre cerveau travail en réponse à un monde dynamique en perpétuel changement. Pendant ma thèse, j'ai ainsi étudié comment des événements multisensoriels impactent notre perception immédiate et/ou ultérieure et comment ils sont traités par notre cerveau. Dans l'étude " Looming signals reveal synergistic principles of multisensory integration" (Cappe, Thelen et al., 2012), nous nous sommes intéressés aux processus neuronaux impliqués dans la détection de mouvements à l'aide de l'utilisation de stimuli audio-visuels seuls ou combinés. Nos résultats ont montré que notre cerveau intègre de manière préférentielle des stimuli audio-visuels combinés s'approchant de l'observateur. De plus, nous avons montré que des effets précoces, observés au niveau de la réponse cérébrale, influencent notre comportement, en accélérant la détection de ces stimuli. Dans l'étude "Electrical neuroimaging of memory discrimination based on single-trial multisensory learning" (Thelen et al., 2012), nous nous sommes intéressés à l'impact qu'a la présentation d'un stimulus audio-visuel sur l'exactitude de reconnaissance d'une image. Nous avons étudié comment la présentation d'une combinaison audio-visuelle sans signification, impacte, au niveau comportementale et cérébral, sur la reconnaissance ultérieure de l'image. Les résultats ont montré que l'exactitude de la reconnaissance d'images, présentées dans le passé, avec un son sans signification, est inférieure à celle obtenue dans le cas d'images présentées seules. De plus, notre cerveau différencie ces deux types de stimuli très tôt dans le traitement d'images. Dans l'étude "Single-trial multisensory memories affect later visual and auditory object recognition" (Thelen et al., in review), nous nous sommes posés la question si l'exactitude de ia reconnaissance de sons était affectée de manière semblable par la présentation d'événements multisensoriels passés. Ceci a été vérifié par nos résultats. Nous avons proposé que cette similitude puisse être expliquée par le recrutement différentiel d'un réseau neuronal commun.