This study evaluated whether picture exchange communication system (PECS) training would result in the development of conditional relations among corresponding pictures, objects (reinforcers) and spoken words used in PECS training with learners with developmental disabilities. Three participants with autism and mental retardation were trained to use PECS. Match-to-sample procedures were used to assess all possible conditional relations among stimuli before, during, and after PECS training. None of the three participants in this study acquired conditional discriminations involving the pictures, reinforcers, and spoken words used in their PECS training.

The differential outcomes effect (DOE) refers to an observed increase in rates of acquisition of simple or conditional relations when the contingencies of reinforcement arrange for reinforcers to be uniquely correlated with a particular stimulus or response relative to conditions where the reinforcers are not uniquely correlated with either stimulus or response. This effect has been robustly documented in the literature with nonhuman subjects. This study asked whether the DOE would be observed with children with autism spectrum disorder (ASD) learning audio-visual conditional relations. Two participants learned two sets of 3 audio-visual conditional relations. For one set, the training conditions arranged for each of the three conditional relations to be uniquely correlated with a particular reinforcing stimulus (the DO condition). For the second set, the training conditions arranged for the same reinforcer to be used for all three audio-visual conditional relations (the NDO condition). Early results show that audio-visual conditional relations were acquired faster under the DO condition relative to the NDO outcomes condition (accuracy in DO condition was 30.8% higher on average than in NDO condition). These data suggest that differential outcomes should be more thoroughly investigated with children with diagnoses of ASD.

Made available in DSpace on 2016-04-29T13:18:02Z (GMT). No. of bitstreams: 1 pre-versao eletronica.pdf: 1665329 bytes, checksum: fb0986a0146d93d0706058a1172c3b0c (MD5) Previous issue date: 2005-04-29 / The purpose of this research was to analyze the production of observing responses (OR) emitted by humans when the consequences were the production of stimuli related to a VI or EXT schedule. Six participants between 22 and 42 years old were distributed in 2 groups. Participants in Group 1 were first exposed to a multiple schedule VI 20s-EXT with components of 90 seconds in average. During the VI component, presses on a button produced points exchanged for money at the end of each session. After achieving 0.9 or more in a discrimination index (responses during VI divided by responses during VI plus responses during EXT) for 3 or more consecutive sessions, these participants were exposed to a mixed schedule VI 20s-EXT, with the possibility of emiting responses (OR) on a second button that changed the schedule from mixed to its multiple equivalent for the time the button remained pressed. Group 2 participants were exposed directly to this second condition. Participants of Group 2 achived discrimination indexes higher than 0,9 and Group 1 participants did not achived the criterion. The absence of dircrimination of the responses of Group 1 participants was discussed in terms of relevance of the stimuli produced by the OR and in terms of accidental chaining. All participants exposed to the mix VI EXT with OR produced OR. Two participants emitted OR in a situation where they represented effort economy. All participants produced the stimulus related to EXT in geater or equal frequency and duration than the stimulus related to VI / O objetivo desta pesquisa foi analisar situações relacionadas à produção de respostas de observação (RO) emitidas por humanos quando as conseqüências eram a produção de estímulos relacionados a um esquema VI ou a EXT. Seis participantes, com idades entre 22 e 42 anos, foram distribuídos em dois grupos. Os participantes do Grupo 1 foram primeiro expostos a um esquema múltiplo VI 20s-EXT com componentes de 90 segundos em média. Durante os componentes VI, pressões em um botão produziam pontos que eram trocados por dinheiro ao final da sessão. Após atingir um índice de discriminação de 0,9 ou mais (respostas durante VI dividido pela soma das respostas durante VI com as respostas durante EXT) por três ou mais sessões consecutivas, os participantes seriam expostos a um esquema misto VI 20s-EXT, com possibilidade de emissão de respostas (RO) em um segundo botão que mudavam o esquema de misto para seu equivalente em múltiplo pelo tempo que o botão permanecesse pressionado. Os participantes do Grupo 2 foram expostos diretamente a esta segunda condição. Os participantes do Grupo 2 atingiram índices de discriminação maiores que 0,9 e os participantes do Grupo 1 não atingiram este critério. A ausência de discriminação nas respostas dos participantes do Grupo 1 foi discutida em termos da relevância dos estímulos produzidos pela RO e em termos da possibilidade de encadeamento acidental. Todos os participantes expostos ao mix VI EXT com resposta de observação produziram respostas de observação. Dois participantes do Grupo 2 emitiram RO numa situação em que estas representavam economia de esforço. Estímulos relacionados com EXT foram produzidos com maior ou igual freqüência e duração que os estímulos relacionados com VI

This thesis focuses on several aspects of olfactory processing in Drosophila. In chapter I and II, I will discuss how odorants are encoded in the brain. In both insects and mammals, olfactory receptor neurons (ORNs) expressing the same odorant receptor gene converge onto the same glomerulus. This topographical organization segregates incoming odor information into combinatorial maps. One prominent theory suggests that insects and mammals discriminate odors based on these distinct combinatorial spatial codes. I tested the combinatorial coding hypothesis by engineering flies that have only one class of functional ORNs and therefore cannot support combinatorial maps. These files can be taught to discriminate between two odorants that activate the single functional class of ORN and identify an odorant across a range of concentrations, demonstrating that a combinatorial code is not required to support learned odor discrimination. In addition, these data suggest that odorant identity can be encoded as temporal patterns of ORN activity. Behaviors are influenced by motivational states of the animal. Chapter III of this thesis focuses on understanding how motivational states control behavior. Appetitive memory in Drosophilaprovides an excellent system for such studies because the motivational state of hunger promotes reliance on learned appetitive cues whereas satiety suppresses it. We found that activation of neuropeptide F (dNPF) neurons in fed flies releases appetitive memory performance from satiety-mediated suppression. Through a GAL4 screen, we identified six dopaminergic neurons that are a substrate for dNPF regulation. In satiated flies, these neurons inhibit mushroom body output, thereby suppressing appetitive memory performance. Hunger promotes dNPF release, which blocks the inhibitory dopaminergic neurons. The motivational drive of hunger thus affects behavior through a hierarchical inhibitory control mechanism: satiety inhibits memory performance through a subset of dopaminergic neurons, and hunger promotes appetitive memory retrieval via dNPF-mediated disinhibition of these neurons. The aforementioned studies utilize sophisticated genetic tools for Drosophila. In chapter IV, I will talk about two new genetic tools. We developed a new technique to restrict gene expression to different subsets of mushroom body neurons with unprecedented precision. We also adapted the light-activated adenylyl cyclase (PAC) from Euglena gracilis as a light-inducable cAMP system for Drosophila. This system can be used to induce cAMP synthesis in targeted neurons in live, behaving preparations.

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