Notre étude porte sur l’organisation du lexique des verbes chez l’aphasique, d’une part à travers une étude exploratoire en dénomination orale d’action sur support vidéo, et d’autre part à partir d’une investigation en IRMf chez le sujet sain. D’après nos résultats, les aphasiques de différents types ont des difficultés à produire des verbes, et on observe une production importante d’énoncés non conventionnels à pivot verbal : les approximations sémantiques. En aphasiologie, l’étude de ces énoncés, qu’on associe à des paraphasies sémantiques, se limite à un cadre nominal et sont considérés comme des erreurs. Nous soulignons qu’elles manifestent un mode de structuration du lexique des verbes par proximité sémantique et marquent l’existence d’une flexibilité cognitive dans la structuration du lexique mental. Dans la littérature, les troubles spécifiques du verbe, chez l’aphasique, sont associés à des lésions du lobe frontal, mais ces données sont controversées. En IRMf, nous obtenons des activations fronto-pariétales, des régions plus postérieures, et des activations de la boucle fronto-thalamo-striée. Nos résultats sont en faveur d’un recrutement d’un ensemble de régions cérébrales. Le support que nous avons utilisé permettrait d'accéder par deux voies à la représentation de la nature sensori-motrice du verbe, par le gyrus temporal moyen gauche et les aires prémotrices. Le mode vidéo semblerait être un outil d’évaluation plus écologique que le support imagé pour l’étude du traitement du lexique des verbes. / Our study deals with the organisation of verb lexicon in aphasics, partly through an exploratory study of oral action naming using a video stimulus, and partly through an fMRI investigation in healthy subjects. According to our results, patients with different types of aphasia experience verb production difficulties. We observed a high rate of non conventional utterances, mainly verbal, in the form of semantic approximations. In aphasiology, the study of these utterances, which are associated with semantic paraphasia and are considered as errors, is limited to a nominal framework. We emphasise that these utterances demonstrate a verb lexicon structure based on semantic proximity, and signal the existence of a cognitive flexibility in the structure of the mental lexicon. In the literature, specific verb difficulties in aphasics are associated with frontal lobe lesions, but these data have been disputed. Using fMRI, we obtained fronto-parietal activations in the more posterior regions as well as activations in the thalamo-fronto-striate loop. Our results support the recruitment of all the cerebral regions. The stimulus used in our study may have enabled access via two pathways to the representation of the sensorimotor nature of verbs via the left middle temporal gyrus and the premotor areas. Videos appear to be a more ecological evaluative tool than images for studying the lexical processing of verbs.

Ten experiments examined the interactions between vision and audition in stimulusdriven spatial attention orienting and inhibition of return (IOR). IOR is the demonstration that subjects are slower to respond to stimuli that are presented at a previously stimulated location. In each experiment, subjects made go/no-go responses to peripheral targets but not to central targets. On every trial, a target was preceded by a sensory event, called a "cue," either in the same modality (intramodal conditions) or in a different modality (crossmodal conditions). The cue did not predict the location of the target stimulus in any experiment. In some experiments, the cue and target modalities were fixed and different. Under these conditions, response times to a visual target were shorter when it appeared at the same location as an auditory cue than when it appeared on the opposite side of fixation, particularly at short (100 ms) cue-target stimulus onset asynchronies (Experiments 1A and IB). Similarly, response times to an auditory target were shorter when it appeared at the same location as a visual cue than when it appeared at a location on the opposite side of fixation (Experiments 2A and 2B). These crossmodal effects indicate that stimulus-driven spatial attention orienting might arise from a single supramodal brain mechanism. IOR was not observed in either crossmodal experiment indicating that it might arise from modality specific mechanisms. However, for many subjects, IOR did occur between auditory cues and visual targets (Experiments 3A and 3B) and between visual cues and auditory targets (Experiment 4A and 4B) when the target could appear in the same modality as the cue on half of the trials. Finally, the crossmodal effects of stimulus-driven spatial attention orienting on auditory and visual event-related brain potentials (ERPs) were examined in the final two experiments. Auditory cues modulated the ERPs to visual targets and visual cues modulated the ERPs to auditory targets, demonstrating that the mechanisms for spatial attention orienting cannot be completely modality specific. However, these crossmodal ERP effects were very different from each other indicating that the mechanisms for spatial attention orienting cannot be completely shared. / Arts, Faculty of / Psychology, Department of / Graduate

Training structures have been defined as the order and arrangement of baseline conditional discriminations within stimulus equivalence training. The three training structures most often used are, linear (trains A:B and B:C discrimination), many-to-one (trains B:A and C:A discriminations) , and one-to-many (trains A:B and A:C discriminations). Each training structure trains a different set of simultaneous and successive discriminations that are then needed in the test for derived relations (symmetry, reflexivity, transitivity, and symmetrical transitivity). The present experiment seeks to extend the research on stimulus equivalence training structures by using a within-subject design and adult human subjects. Three sets of 9 arbitrary stimuli were trained concurrently each with a different training structure. From the beginning, training and testing trials were intermixed. The likelihood of producing stimulus equivalence formation was equal across structures.

The research investigated the impact of sexual harassment on withdrawal behaviors and attitudes toward harassment by examining the gender composition of the harassment dyad and the organizational status of the perpetrator in relation to the victim. Archival data from the Inter-University Consortium for Political and Social Research at the University of Michigan was used to obtain surveys in which participants rated their attitudes and experiences related to sexual harassment. Only individuals who reported experiencing sexual harassment within the 24 months prior to data collection are included in the current research. A MANOVA was conducted to determine if withdrawal behaviors and attitudes of victims varied by the gender dyad and/or the organizational status of the perpetrator. Results indicated that individuals harassed by people with higher organizational status displayed more withdrawal behaviors in the form of decreased productivity and increased use of sick, annual, and unpaid leave. Individuals harassed by a member of the same gender also used more unpaid leave. Interestingly, individuals harassed by members of the opposite gender, tended to disagree more strongly with the attitude index measuring cautious awareness of sexual harassment.

The current study investigated concept formation in domestic dogs, specifically that of a toy concept. The dog's differential responding (retrieval vs. non-retrieval) to two sets of stimuli suggested a toy concept. Differential responding occurred from the very first trial, indicating that the concept had been formed in the natural environment, not during the experiment. It was hypothesized that a common response may be responsible for the emergence of the class in the natural environment. The results demonstrated that it was possible to expand the class by adding previously non-retrieved objects to the toy class through a common response. It was also shown that the toy concept passed the more stringent criterion (transfer of function test) required validating it as a concept.

Les microgels sont des particules colloïdales polymères faiblement réticulées, capables de se gonfler d’un solvant, de se déformer et de s’adsorber à des interfaces liquides. Parmi eux, les microgels de poly(N-isopropylacrylamide) (pNIPAM) sont thermosensibles et présentent une contraction en volume lorsque la température est supérieure à la température de transition de phase volumique, notée VPTT. De précédents travaux ont montré leur capacité à stabiliser des émulsions de Pickering : les émulsions peuvent être stables à des températures inférieures à la VPTT et être déstabilisées sur demande au-dessus de celle-ci. Afin d’approfondir la compréhension du mécanisme de stabilisation des émulsions, nous discutons le rôle de la structure des microgels sur leur adsorption, leur organisation à des interfaces modèles, les propriétés mécaniques des interfaces et les propriétés des émulsions résultantes en terme de stabilité (cinétique, mécanique) et de propriétés d’écoulement. Le rôle de la réticulation, de la présence de charges et de la taille est étudié pour le modèle du pNIPAM. Nous démontrons le lien existant entre conformation et propriétés macroscopiques des émulsions. En prenant en considération à la fois la structure des microgels et les procédés de formulation (voies d’émulsification), des émulsions avec des propriétés rhéologiques et des états de floculation variés peuvent être obtenues. Fort de ces connaissances, les concepts établis à l’aide des microgels de pNIPAM seront généralisés à d’autres familles de microgels, d’une part des systèmes biocompatibles avec des dérivés comportant des chaînes pendantes oligo(éthylène oxyde), d’autre part des microgels sensibles à des stimuli biologiques tels que la reconnaissance de sucre. / Microgels are soft and deformable colloidal particles that are swollen by a solvent and display the ability to deform and adsorb at liquid interfaces. The poly(N-isopropylacrylamide) (pNIPAM) microgels are thermo-sensitive and exhibit a volume contraction when the temperature is raised above the volume phase transition temperature (VPTT). These particle have shown high potential as Pickering emulsions stabilizers: emulsions could be stable at ambiant temperature, below the VPTT and destabilize on-demand above it. To get insight into understanding of the emulsion stabilization mechanism, we systematically discuss the relation between the microgel structure, their adsorption, their organization at model interfaces, the viscoelastic behavior of the interface and the resulting emulsions properties in terms of stability and flow behavior. In the present work, using pNIPAM as model microgels, we investigate the effect of their cross-linking density, their size and their charge density. Varying the microgels structures and the formulation conditions (emulsification process), we could control the emulsions flocculation state and rheological behavior. Based on this knowledge, we propose to synthesize new biocompatible microgels as emulsion stabilizers. Using ligand-modified microgels sucrose-sensitive emulsions may be obtained, enlarging the possible application domains.

Sidman's (2000) theory of stimulus equivalence predicts an interaction between the development of analytic units and the development of equivalence relations. Previous research has documented these interactions (stewart, Barnes-Holmes, Roche, & Smeets, 2002; Vaidya & Brackney, 2014), therefore the current study attempted to replicate the effects seen in Vaidya & Brackney, 2014 (Experiment 2). Baseline conditional discriminations were trained for two sets of three, three-member classes, while participants simply observed stimuli in the third set which was arranged identical to those of Sets 1 and 2. Following equivalence tests where performance met the accuracy criterion of 85% for Sets 1 and 2, participants then entered a simple successive discrimination training phase where common responses were then trained with an equivalence class (pressing the Q key in the presence of A1, B1, or C1), cross equivalence classes (pressing the R key in the presence of A4, A5, or A6), or for stimuli where the participants had experience with them, but the contingencies were never arranged to facilitate equivalence class formation. Results showed a facilitative effect for common responses drawn from within equivalence classes (Set 1), and a retardation effect for common responses drawn from across equivalence classes (Set 2), for three of the five participants. Results for Set 3 showed an acquisition that fell intermediate to that of Sets 1 and 2, respectively, suggesting an interaction occurring between existing equivalence relations and the development of analytic units.

Relaxation procedures and anxiety relief were reviewed. Effects of cognitive and expectancy variables in reduction of avoidance behavior were also extensively reviewed. Various theoretical models for desensitization were presented. Use of symbolic control in classical conditioning and use of self-control methods in anxiety reduction were discussed. Special emphasis was given to self-desensitization and cue controlled relaxation. One goal of the experiment was to determine whether a musical stimulus associated with counter anxiety procedures could reduce or prevent subjects' phobic responses in the presence of the phobic situation. Another goal was to determine the relative efficacy of two counter anxiety procedures (anxiety relief and progressive muscle relaxation) in lowering muscle tension and in reducing or preventing speech anxiety. Several implications were drawn from the study. Relaxation alone may alleviate anxiety and phobic behavior without being paired with phobic stimuli. Cognitive variables such as expectancy and feedback of progress make a substantial contribution to treatment of situational anxiety. Progressive muscle relaxation may not be the technique of choice for producing low levels of muscle tension. Recommendations for future research were specified, including additional measures and control procedures.

The purpose of this experiment was to study the effects of training history on retention and re-acquisition of stimulus control of previously learned behaviors. In Phase I, two pairs of behaviors were alternately trained. Circle and touch behaviors were trained concurrently until two consecutive errorless sessions were run. Spin and down behaviors were trained together in the same manner. Probe sessions, in which all four cues were presented, were conducted each time a pair of behaviors reached this criterion. Training of one pair did not occur until the other pair had reached criterion and probe sessions were run. Despite achieving the designated criterion during training, stimulus control changed during probes. During probe sessions, errors increased under the cues that were not currently being trained. In most cases, the type of errors emitted for each cue was the same as the behavior that was trained concurrently. The number of training sessions required to reach criterion accuracy was high during the first set of sessions and decreased over the course of the experiment. In Phase II, spin and circle behaviors were trained concurrently. The number of sessions required to reach stimulus control criteria remained low, and the number of errors emitted under the spin and circle cues during probe sessions decreased. However, the number of errors increased under the touch cue. In Phase III, a reinforce-all procedure was used instead of extinction to test stimulus control. The highest frequency of errors occurred under the touch cue, but the down error was almost exclusively emitted under every cue during the last several sessions.

Dog trainers sometimes teach verbal cues by saying the cue as the dog is performing the desired behavior. However, there is disagreement about when to say the cue. In this study, a pet dog was trained to go to three different apparatus, the cue for each of which was given at a different time, in a multi-element design. The cue "hoop" was given just as the dog began to move to the hoop apparatus. The cue "carrier" was given as the dog was stepping into the carrier apparatus. The cue "platform" was given after the dog was sitting on the platform apparatus. To test if the dog had learned the cues, the trainer had the dog sit and gave the cue. During testing, if only the correct apparatus was present, the dog responded to all three cues. However, when all three apparatus were present, the dog only responded correctly to the "hoop" cue. This suggests that giving the cue just as the learner is beginning to perform the desired behavior is the most effective teaching method.