Orthogonal higher order structure and confirmatory factor analysis of the French Wechsler Adult Intelligence Scale (WAIS-III).

According to the most widely accepted Cattell-Horn-Carroll (CHC) model of intelligence measurement, each subtest score of the Wechsler Intelligence Scale for Adults (3rd ed.; WAIS-III) should reflect both 1st- and 2nd-order factors (i.e., 4 or 5 broad abilities and 1 general factor). To disentangle the contribution of each factor, we applied a Schmid-Leiman orthogonalization transformation (SLT) to the standardization data published in the French technical manual for the WAIS-III. Results showed that the general factor accounted for 63% of the common variance and that the specific contributions of the 1st-order factors were weak (4.7%-15.9%). We also addressed this issue by using confirmatory factor analysis. Results indicated that the bifactor model (with 1st-order group and general factors) better fit the data than did the traditional higher order structure. Models based on the CHC framework were also tested. Results indicated that a higher order CHC model showed a better fit than did the classical 4-factor model; however, the WAIS bifactor structure was the most adequate. We recommend that users do not discount the Full Scale IQ when interpreting the index scores of the WAIS-III because the general factor accounts for the bulk of the common variance in the French WAIS-III. The 4 index scores cannot be considered to reflect only broad ability because they include a strong contribution of the general factor.

Antiretroviral treatment of adult HIV infection: 2014 recommendations of the International Antiviral Society-USA Panel.

IMPORTANCE: New data and antiretroviral regimens expand treatment choices in resource-rich settings and warrant an update of recommendations to treat adults infected with human immunodeficiency virus (HIV). OBJECTIVE: To provide updated treatment recommendations for adults with HIV, emphasizing when to start treatment; what treatment to start; the use of laboratory monitoring tools; and managing treatment failure, switches, and simplification. DATA SOURCES, STUDY SELECTION, AND DATA SYNTHESIS: An International Antiviral Society-USA panel of experts in HIV research and patient care considered previous data and reviewed new data since the 2012 update with literature searches in PubMed and EMBASE through June 2014. Recommendations and ratings were based on the quality of evidence and consensus. RESULTS: Antiretroviral therapy is recommended for all adults with HIV infection. Evidence for benefits of treatment and quality of available data increase at lower CD4 cell counts. Recommended initial regimens include 2 nucleoside reverse transcriptase inhibitors (NRTIs; abacavir/lamivudine or tenofovir disoproxil fumarate/emtricitabine) and a third single or boosted drug, which should be an integrase strand transfer inhibitor (dolutegravir, elvitegravir, or raltegravir), a nonnucleoside reverse transcriptase inhibitor (efavirenz or rilpivirine) or a boosted protease inhibitor (darunavir or atazanavir). Alternative regimens are available. Boosted protease inhibitor monotherapy is generally not recommended, but NRTI-sparing approaches may be considered. New guidance for optimal timing of monitoring of laboratory parameters is provided. Suspected treatment failure warrants rapid confirmation, performance of resistance testing while the patient is receiving the failing regimen, and evaluation of reasons for failure before consideration of switching therapy. Regimen switches for adverse effects, convenience, or to reduce costs should not jeopardize antiretroviral potency. CONCLUSIONS AND RELEVANCE: After confirmed diagnosis of HIV infection, antiretroviral therapy should be initiated in all individuals who are willing and ready to start treatment. Regimens should be selected or changed based on resistance test results with consideration of dosing frequency, pill burden, adverse toxic effect profiles, comorbidities, and drug interactions.

Assessment of adult formulas for glomerular filtration rate estimation in children.

BACKGROUND: Estimated glomerular filtration rate (eGFR) is an important diagnostic instrument in clinical practice. The National Kidney Foundation-Kidney Disease Quality Initiative (NKF-KDOQI) guidelines do not recommend using formulas developed for adults to estimate GFR in children; however, studies confirming these recommendations are scarce. The aim of our study was to evaluate the accuracy of the new Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formula, the Modification of Diet in Renal Disease (MDRD) formula, and the Cockcroft-Gault formula in children with various stages of chronic kidney disease (CKD). METHODS: A total of 550 inulin clearance (iGFR) measurements for 391 children were analyzed. The cohort was divided into three groups: group 1, with iGFR >90 ml/min/1.73 m(2); group 2, with iGFR between 60 and 90 ml/min/1.73 m(2); group 3, with iGFR of <60 ml/min/1.73 m(2). RESULTS: All formulas overestimate iGFR with a significant bias (p < 0.001), present poor accuracies, and have poor Spearman correlations. For an accuracy of 10 %, only 11, 6, and 27 % of the eGFRs are accurate when using the MDRD, CKD-EPI, and Cockcroft-Gault formulas, respectively. For an accuracy of 30 %, these formulas do not reach the NKF-KDOQI guidelines for validation, with only 25, 20, and 70 % of the eGFRs, respectively, being accurate. CONCLUSIONS: Based on our results, the performances of all of these formulas are unreliable for eGFR in children across all CKD stages and cannot therefore be applied in the pediatric population group.

Anti-basal ganglia antibodies and Tourette's syndrome: a voxel-based morphometry and diffusion tensor imaging study in an adult population.

Anti-basal ganglia antibodies (ABGAs) have been suggested to be a hallmark of autoimmunity in Gilles de la Tourette's syndrome (GTS), possibly related to prior exposure to streptococcal infection. In order to detect whether the presence of ABGAs was associated with subtle structural changes in GTS, whole-brain analysis using independent sets of T(1) and diffusion tensor imaging MRI-based methods were performed on 22 adults with GTS with (n = 9) and without (n = 13) detectable ABGAs in the serum. Voxel-based morphometry analysis failed to detect any significant difference in grey matter density between ABGA-positive and ABGA-negative groups in caudate nuclei, putamina, thalami and frontal lobes. These results suggest that ABGA synthesis is not related to structural changes in grey and white matter (detectable with these methods) within frontostriatal circuits.

Mycophenolic acid formulations in adult renal transplantation - update on efficacy and tolerability.

The description more than 30 years ago of the role of de novo purine synthesis in T and B lymphocytes clonal proliferation opened the possibility for selective immunosuppression by targeting specific enzymatic pathways. Mycophenolic acid (MPA) blocks the key enzyme inosine monophosphate dehydrogenase and the production of guanosine nucleotides required for DNA synthesis. Two MPA formulations are currently used in clinical transplantation as part of the maintenance immunosuppressive regimen. Mycophenolate mofetil (MMF) was the first MPA agent to be approved for the prevention of acute rejection following renal transplantation, in combination with cyclosporine and steroids. Enteric-coated mycophenolate sodium (EC-MPS) is an alternative MPA formulation available in clinical transplantation. In this review, we will discuss the clinical trials that have evaluated the efficacy and safety of MPA in adult kidney transplantation for the prevention of acute rejection and their use in new combination regimens aiming at minimizing calcineurin inhibitor toxicity and chronic allograft nephropathy. We will also discuss MPA pharmacokinetics and the rationale for therapeutic drug monitoring in optimizing the balance between efficacy and safety in individual patients.

Incidenceof out-of-hospital adult nontraumatic cardiac arrest presenting as a convulsion

Introduction: The majority of convulsions are due to an epileptic seizure or a convulsive syncope. The incidence of out-of-hospital cardiac arrest (OH-CA) presenting as a convulsion is unknown. Objective: This study aimed to measure the incidence of adult nontraumatic OH-CA presenting as a convulsion, a rate that has not been published so far, to the best of our knowledge. Methods: We prospectively collected all incoming calls with an out-of-hospital nontraumatic seizure as the chief complaint in patients >18 years old during a 24-month period. Among these calls, we collected cases identified as OH-CA by paramedics. Results: During the 24-month period, the emergency medical services (EMS) dispatch center received 561 calls for an out-of-hospital nontraumatic convulsion in an adult. Twelve cases were ultimately classified as CA. In this group, one bystander spontaneously reported that the patient was known for epilepsy. The incidence of OH-CA presenting as convulsions was therefore 2.1% of all calls for convulsion. Over the same period, the EMS dispatch center received 1,035 calls related to an adult nontraumatic OH-CA. Therefore, the rate of OH-CA presenting as a convulsion represented 1.2% of all adult nontraumatic OH-CA. Conclusion:L Only 12 cases out of the 531 calls for nontraumatic adult convulsions were confirmed OHCA (2.1%). Nevertheless, this unusual presentation of OH-CA must be recognized by dispatchers, even when a patient is reported by bystander as a known epileptic. Dispatchers should keep bystanders on the line or call them back before paramedics' arrival, and have them confirm the progressive return of a normal pat- tern of breathing and state of consciousness; if not, they should encourage the bystander to initiate CPR when necessary. An intervention should be implemented to improve the detection by dispatchers of OH-CA presenting as convulsion by the development of a specific interview and directed observation. For dispatchers, a past medical history of epilepsy should not be regarded as sufficient information to rule out OH-CA. It is mandatory that known epileptic patients should be monitored in the same way as nonepileptic patients.

Quality Of Attachment, Perinatal Risk, And Mother-Infant Interaction In A High-Risk Premature Sample

Thirty-three families, each with a premature infant born less than 33 gestational weeks, were observed in a longitudinal exploratory study. Infants were recruited in a neonatal intensive care unit, and follow-up visits took place at 4 months and 12 months of corrected age. The severity of the perinatal problems was evaluated using the Perinatal Risk Inventory (PERI; A.P. Scheiner & M.E. Sexton, 1991). At 4 months, mother infant play interaction was observed and coded according to the CARE-index (P.M. Crittenden, 2003); at 12 months, the Strange Situation Procedure (SSP; M.D.S. Ainsworth, M.C. Blehar, E. Waters. & S. Wall, 1978) was administered. Results indicate a strong correlation between the severity of perinatal problems and the quality of attachment at 12 months. Based on the PERI, infants with high medical risks more frequently tended to be insecurely attached. There also was a significant correlation between insecure attachment and dyadic play interaction at 4 months (i.e., maternal controlling behavior and infant compulsive compliance). Moreover, specific dyadic interactive patterns could be identified as protective or as risk factors regarding the quality of attachment. Considering that attachment may have long-term influence on child development, these results underline the need for particular attention to risk factors regarding attachment among premature infants.

Enhanced Proinflammatory Cytokine Response to Bacterial Lipopolysaccharide in the Adult Male Rat after either Neonatal or Prepubertal Ablation of Biological Testosterone Activity.

A sex steroid-dependent modulation of the immune function in mammals is accepted, and evidence suggests that while estrogens enhance, androgens inhibit the immune response. The aim of this study was to explore in the adult male rat the effect of either neonatal flutamide (FTM) treatment or prepubertal orchidectomy (ODX) on endocrine markers in the basal condition and peripheral tumor necrosis factor alpha (TNFα) levels during inflammatory stress. For these purposes, (1) 5-day-old male rats were subcutaneously injected with either sterile vehicle alone or containing 1.75 mg FTM, and (2) 25-day-old male rats were sham operated or had ODX. Rats were sacrificed (at 100 days of age) in the basal condition for determination of peripheral metabolite levels. Additional rats were intravenously injected with bacterial lipopolysaccharide (LPS; 25 μg/kg body weight, i.v.) and bled for up to 4 h. Data indicate that (1) ODX increased peripheral glucocorticoid levels and reduced those of testosterone, whereas FTM-treated rats displayed low circulating leptin concentrations, and (2) LPS-induced TNFα secretion in plasma was significantly enhanced in the FTM and ODX groups. Our study supports that neonatal FTM treatment affected adiposity function, and adds data maintaining that androgens have a suppressive role in proinflammatory cytokine release in plasma during inflammation.

Genome-wide association analysis identifies 20 loci that influence adult height.

Adult height is a model polygenic trait, but there has been limited success in identifying the genes underlying its normal variation. To identify genetic variants influencing adult human height, we used genome-wide association data from 13,665 individuals and genotyped 39 variants in an additional 16,482 samples. We identified 20 variants associated with adult height (P < 5 x 10(-7), with 10 reaching P < 1 x 10(-10)). Combined, the 20 SNPs explain approximately 3% of height variation, with a approximately 5 cm difference between the 6.2% of people with 17 or fewer 'tall' alleles compared to the 5.5% with 27 or more 'tall' alleles. The loci we identified implicate genes in Hedgehog signaling (IHH, HHIP, PTCH1), extracellular matrix (EFEMP1, ADAMTSL3, ACAN) and cancer (CDK6, HMGA2, DLEU7) pathways, and provide new insights into human growth and developmental processes. Finally, our results provide insights into the genetic architecture of a classic quantitative trait.

Attachment among Adoptive Families: Two Emipirical Studies in an International Context

The present dissertation analyzed the construct of attachment at different time points, specifically focusing on two phases of adoptive family life that have so far received little attention from investigators. Study 1 focused on the first months of adoption, and analyzed the development of the attachment relationship to new caregivers. The sample was composed of a small but homogeneous group (n=6) of Korean-born children, adopted by Italian parents. The Parent Attachment Diary (Dozier & Stovall, 1997) was utilized to assess the child's attachment behavior. We assessed these behavior for the first 3 months after placement into adoption. Results showed a double variability of attachment behavior: within subjects during the 3-months, and between subjects, with just half of the children developing a stable pattern of attachment. In order to test the growth trajectories of attachment behavior, Hierarchical Linear Models (Bryk & Raudenbush, 1992) were also applied, but no significant population trend was identified. Study 2 analyzed attachment among adoptees during the sensitive period of adolescence. Data was derived from an international collection (n= 104, from Belgium Italy, and Romania) of semi-structured clinical interviews (with adolescents and with their adoptive parents), as well as from questionnaires. The purpose of this study was to detect the role played by risk and protective factors on the adoptee's behavioral and socio-emotional outcomes. In addition, we tested the possible interactions between the different attachment representations within the adoptive family. Results showed that pre-adoptive risk predicted the adolescent's adjustment; however, parental representations constituted an important moderator of this relationship. Moreover, the adolescent's security of attachment partially mediated the relationship between age at placement and later behavioral problems. In conclusion, the two present attachment studies highlighted the notable rate of change of attachment behavior over time, which showed its underlying plasticity, and thus the possible reparatory value of the adoption practice. Since parents have been proven to play an important role, especially in adolescence, the post-adoption support acquires even more importance in order to help parents promoting a positive and stable relational environment over time. - L'objectif de cette thèse est de décrire la formation des relations d'attachement chez les enfants et les adolescents adoptés, lors de deux phases particulières de la vie de la famille adoptive, qui ont été relativement peu étudiées. L'Étude 1 analyse les premiers mois après l'adoption, avec le but de comprendre si, et comment, une relation d'attachement aux nouveaux parents se développe. L'échantillon est composé d'un petit groupe (n = 6) d'enfants provenant de Corée du Sud, adoptés par des parents Italiens. A l'aide du Parent Attachment Diary (Dozier & Stovall, 1997), des observations des comportements d'attachement de l'enfant ont été recueillies chaque jour au cours des 3 premiers mois après l'arrivée. Les résultats montrent une double variabilité des comportements d'attachement: au niveau inter- et intra-individuel ; au premier de ces niveaux, seuleme la moitié des enfants parvient à développer un pattern stable d'attachement ; au niveau intra-individuel, les trajectoires de développement des comportements d'attachement ont été testées à l'aide de Modèles Linéaires Hiérarchiques (Bryk et Raudenbush, 1992), mais aucune tendance significative n'a pu être révélée. L'Étude 2 vise à analyser l'attachement chez des enfants adoptés dans l'enfance, lors de la période particulièrement sensible de l'adolescence. Les données sont issues d'un base de données internationale (n = 104, Belgique, Italie et Roumanie), composée d' entretiens cliniques semi-structurées (auprès de l'adolescents et des ses parents adoptifs), ainsi que de questionnaires. Les analyses statistiques visent à détecter la présence de facteurs de risque et de protection relativement à l'attachement et aux problèmes de comportement de l'enfant adopté. En outre, la présence d'interactions entre les représentations d'attachement des membres de la famille adoptive est évaluée. Les résultats montrent que les risques associés à la période pré-adoptive prédisent la qualité du bien-être de l'adolescent, mais les représentations parentales constituent un modérateur important de cette relation. En outre, la sécurité de l'attachement du jeune adopté médiatise partiellement la relation entre l'âge au moment du placement et les problèmes de comportement lors de l'adolescence. En conclusion, à l'aide de multiples données relatives à l'attachement, ces deux études soulignent son évolution notable au fil du temps, ce qui sous-tend la présence d'une certaine plasticité, et donc la possible valeur réparatrice de la pratique de l'adoption. Comme les parents semblent jouer un rôle important de ce point de vue, surtout à l'adolescence, cela renforce la notion d'un soutien post-adoption, en vue d'aider les parents à la promotion d'un environnement relationnel favorable et stable. - Il presente lavoro è volto ad analizzare l'attaccamento durante le due fasi della vita della famiglia adottiva che meno sono state indagate dalla letteratura. Lo Studio 1 aveva l'obiettivo di analizzare i primi mesi che seguono il collocamento del bambino, al fine di capire se e come una relazione di attaccamento verso i nuovi genitori si sviluppa. Il campione è composto da un piccolo gruppo (n = 6) di bambini provenienti dalla Corea del Sud e adottati da genitori italiani. Attraverso il Parent Attachment Diary (Stovall e Dozier, 1997) sono stati osservati quotidianamente, e per i primi tre mesi, i comportamenti di attaccamento del bambino. I risultati hanno mostrato una duplice variabilità: a livello intraindividuale (nell'arco dei 3 mesi), ed interindividuale, poiché solo la metà dei bambini ha sviluppato un pattern stabile di attaccamento. Per verificare le traiettorie di sviluppo di tali comportamenti, sono stati applicati i Modelli Lineari Gerarchici (Bryk & Raudenbush, 1992), che però non hanno stimato una tendenza significativa all'interno della popolazione. Obiettivo dello Studio 2 è stato quello di esaminare l'attaccamento nelle famiglie i cui figli adottivi si trovavano nella delicata fase adolescenziale. I dati, provenienti da una raccolta internazionale (n = 104, Belgio, Italia e Romania), erano costituiti da interviste cliniche semi-strutturate (con gli adolescenti e i propri genitori adottivi) e da questionari. Le analisi hanno indagato il ruolo dei fattori di rischio sullo sviluppo socio-emotivo e sugli eventuali problemi comportamentali dei ragazzi. Inoltre, sono state esaminate le possibili interazioni tra le diverse rappresentazioni di attaccamento dei membri della famiglia adottiva. I risultati hanno mostrato che il rischio pre-adottivo predice l'adattamento dell'adolescente, sebbene le rappresentazioni genitoriali costituiscano un importante moderatore di questa relazione. Inoltre, la sicurezza dell'attaccamento dell'adolescente media parzialmente la relazione tra età al momento dell'adozione e problemi comportamentali in adolescenza. In conclusione, attraverso i molteplici dati relativi all'attaccamento, i due studi ne hanno evidenziato il cambiamento nel tempo, a riprova della sua plasticità, e pertanto sottolineano il possibile valore riparativo dell'adozione. Dal momento che i genitori svolgono un ruolo importante, soprattutto in adolescenza, il supporto nel post- adozione diventa centrale per aiutarli a promuovere un ambiente relazionale favorevole e stabile nel tempo.

Attachment and temperament in early childhood; implications for later behavior problems.

In the context of a French validation study, the Child Behavior Checklist (CBCL) was administered to more than 3000 French speaking mothers of 5-year-old children. Scores were factor-analyzed. Principal components analysis revealed four dimensions: externalizing and internalizing behavior problems, immaturity and somatoform disorders. Another sample of 40 mothers participated in a longitudinal study, filling in the CBCL when their children were 5 years old. These children had been observed previously in the Strange Situation (SSP) at 21 months. Several dichotomous variables derived from the SSP (e.g. secure versus insecure, proximal versus distal interaction with the mother, avoidant behavior) have been used as predictors of the four dimensions extracted from the CBCL. Hierarchical regressions showed that proximal behaviors with the mother, which reflect temperamental characteristics independently of the quality of attachment, predicted internalizing problems, whereas avoidance of the mother, or insecure-avoidant attachment, predicted internalizing as well as externalizing problems at 5 years of age. These results show that attachment and temperament, as assessed by the SSP, may each have specific implications for later behavior problems.

MOLECULAR REORGANIZATION FOLLOWING SENSORY STIMULATION IN THE ADULT MOUSE BARREL CORTEX

Sensory information is an important factor in shaping neuronal circuits during development and adulthood. In the barrel cortex of adult rodents, cells from layer IV are able to adapt their functional state to an increased flow of sensory information from the mystacial whisker follicles. Previous studies in our group have shown that whisker stimulation induces the formation of inhibitory synapses in the corresponding barrel (Knott et al., 2002) and decreases neuronal responses toward the deflection of the stimulated whisker (Quairiaux et al., 2007). Together these observations have turned the barrel cortex into a model to study homeostatic plasticity. At the cellular level, neuronal activity triggers intracellular signaling cascades leading to a transcriptional response. To further characterize the molecular pathways involved in the synaptic changes after whisker stimulation in the adult mouse, a previous doctoral student in our group performed a microarray analysis on laser-dissected barrels in sections through layer IV. This study identified the regulation (up and down) of a series of genes in the stimulated barrels (thesis of Johnston-Wenger, 2010). We here focused on ten genes that presented the highest fold change according to the microarray analysis. Out of these genes, 7 are known as neuronal activity-dependent genes (Tnncl, Nptx2, Sorcs3, Ptgs2, Nr4a2, Npas4 and Adcyapl) whereas three have so far not been related to neuronal plasticity (Scn7a, Pcdhl5 and Cede3). The study aimed at confirming the results of the microarray analysis and localizing molecular modifications in the stimulated barrel column at the cellular level. In situ hybridization for Pcdhl5 after different periods of whisker stimulation (3, 6, 9, 15, 24 hrs) allowed us to confirm that the 1.25 fold change used for the microarray analysis is an appropriate threshold for considering a regulation significant after sensory-stimulation. Moreover, we confirmed with in situ hybridization a significant upregulation of the genes of interest in the stimulated barrels. In situ hybridization and immunohistochemistry allowed us to observe the distribution of the genes of interest and the corresponding protein products at the cellular level. Three observations were made: 1) alterations of the expression was restricted to the stimulated barrels for all genes tested; 2) within a barrel column not all cells responded to whisker stimulation with an altered gene expression; 3) in the stimulated barrels, two different patterns of mRNA and protein expression can be distinguished. We hypothesize that this segregation of the activity-induced gene expression reflects the segregation of the two principal thalamocortical pathways conveying the sensory information to the barrel cortex. Moreover, only neurons reaching the critical threshold will modify their gene expression program resulting in structural as well as physiological modifications that prevent the subsequent propagation of the excess of excitation to the postsynaptic targets. The activity-induced gene expression is therefore adapted in a cell-type-specific manner to induce a homeostatic response to the entire neuronal network involved in the integration of the sensory information. This to our knowledge the first study showing the distinct, but complementary contribution of the two thalamocortical pathways in experience-dependent plasticity in the adult mouse barrel cortex. -- L'information sensorielle nous permet de continuellement façonner nos circuits neuronaux autant durant le développement qu'à l'âge adulte. Chez le rongeur l'information sensorielle perçue par les vibrisses est intégrée au niveau du cortex somatosensoriel primaire (appelé en anglais « barrel cortex ») dont les cellules de la couche IV sont capables d'adapter leur état fonctionnel en réponse à une augmentation d'activité neuronale. Ce modèle expérimental a permis à notre groupe de recherche d'observer des changements rapides du circuit neuronal en fonction de l'activité sensorielle. En effet, la stimulation continue d'une vibrisse d'une souris adulte pendant 24 heures induit non seulement un remaniement synaptique (Knott et al., 2002), mais également des changements physiologiques au niveau des neurones du tonneau correspondant (Quairiaux et al., 2007). Ces observations nous permettent d'affirmer que le « barrel cortex » est un modèle approprié pour y étudier la plasticité synaptique. Au niveau cellulaire, l'activité neuronale déclenche des cascades de signalisation intracellulaire résultant en une réponse transcriptionnelle. Afin de caractériser les voies moléculaires impliquées dans la plasticité synaptique, une puce à ARN nous a permis de comparer l'expression de gènes entre un tonneau correspondant à une vibrisse stimulée et un tonneau d'une vibrisse non-stimulée (Nathalie). Cette analyse a révélé un certain nombre de gènes régulés de manière positive ou négative par l'augmentation de l'activité neuronale. Nous nous sommes concentrés sur 10 gènes dont l'expression est fortement régulée. L'expression de sept d'entre eux a déjà été démontrée comme dépendante de l'activité neuronale (Tnncl, Nptx2, Sorcs3, Ptgs2, Nr4a2, Npas4 otAdcyapl) alors que l'expression des trois autres (Scn7a, Pcdhl5 et Cedei) n'a pour le moment pas encore été liée à la plasticité neuronale. Le but de cette thèse est de confirmer les résultats de la puce à ARN et de déterminer dans quel type cellulaire ces gènes sont exprimés. L'hybridation in situ pour le gène Pcdhl5, après différentes périodes de stimulation des vibrisses (3, 6, 9, 15 et 24 heures), nous a permis de confirmer que le seuil de 1.25x utilisé dans l'analyse de la puce à ARN est approprié pour considérer qu'un gène est régulé de manière significative par la stimulation sensorielle. Nous avons également pu confirmer à l'aide de cette technique que la stimulation sensorielle augmente significativement l'expression de ces dix gènes. L'expression de ces gènes au niveau cellulaire a été observée à l'aide des techniques d'hybridation in situ et d'immunohistochimie. Trois observations ont été faites : 1) la régulation de ces gènes est restreinte aux tonneaux correspondants aux vibrisses stimulées ; 2) au niveau d'une colonne corticale correspondant aux vibrisses stimulées, seules certaines cellules présentent une altération de leur expression génique ; 3) au niveau des tonneaux stimulés, deux profils d'expression d'ARNm et de protéines sont observés. Notre hypothèse est que cette distribution pourrait correspondre à la terminaison ségrégée des deux voies thalamocortical qui amènent l'information sensorielle dans le cortex cérébral. De plus, seul les neurones atteignant le seuil critique d'activation modifient leur expression génique en réponse à la stimulation sensorielle. Ces changements d'expression géniques vont permettre à la cellule de modifier ses propriétés structurales et physiologiques de manière a prevenir la propagation d'un excès d'activité neuronale au niveau de ses cibles postsynaptics. L'activité neuronale agit donc spécifiquement sur certains types cellulaires de maniere a induire une réponse homéostatique au niveau du réseau neuronal impliqué dans l'integration de l'information sensorielle. Nos travaux démontrent pour une première fois que les deux voies sensorielles contribuent d'une manière distincte et complémentaire à la plasticité corticale induite par un changement de l'activité sensorielle chez la souris adulte.