Semantisk mättnad beskrivs som en tillfällig meningsförlust efter hög upprepning av ett ord. Denna mättnad kan mätas med hjälp av N400, en differensvåg som beräknas utifrån elektroencefalografi (EEG) och uppnås när ett ord avviker från en semantisk kontext. N400 uppnås därför inte vid ord från samma semantiska kontext. En tidigare studie visade N400 vid 3 repetitioner av ett ord men ingen vid 30. Detta tyder på semantisk mättnad efter 30 repetitioner. Syftet med denna studie var att mäta om semantisk mättnad kan uppnås redan vid 15 repetitioner. Detta mättes genom att olika ord repeterades 3, 15 eller 30 gånger för 8 deltagare för att etablera en kontext. På grund av det låga antalet deltagare simulerades data för ytterligare 20 deltagare. Därefter visades ett målord som antingen var relaterat eller orelaterat till det första ordet. Ett t-test på stickprovsmedelvärdet gav inget stöd för N400 vid 3 eller 30 repetitioner, endast vid 15 repetitioner. Med hjälp av beroende t-tester kunde vi fastställa en signifikant minskning av N400 från 15 till 30 repetitioner. Resultaten pekar på att semantisk mättnad sker gradvis och fortsätter även efter 15 repetitioner. Dock bör resultatet tolkas med viss reservation eftersom ingen N400 visades vid 3 repetitioner, trots att N400 bör ha varit störst där.

The phenomenon of attentional bias to alcohol, where drinkers demonstrate a preference in allocating visual attention towards alcohol-related stimuli rather than neutral stimuli, is well-established. Studies detecting this phenomenon typically utilize computer-administered stimulus presentation tasks such as the visual dot probe task. Despite their frequency of use, these tasks do not represent the ways in which individuals typically encounter alcohol outside of the laboratory. Typical environments where alcohol is present allow individuals to move about freely and encounter alcohol while also being exposed to many other stimuli. This dissertation sought to implement a novel approach to assessing attentional bias in vivo, and identify how alcohol consumption might influence such in vivo attentional bias. This two-study dissertation utilized an in vivo task where participants looked freely around a room representing a recreational setting containing numerous objects while portable eye-tracking glasses monitored what an individual looked at and for how long. Target items of alcohol and neutral beverages were placed throughout the environment and fixation time spent on these objects was recorded. The first study of this dissertation examined attentional bias to alcohol-related objects across two identical testing sessions to understand the impact of novelty on allocation of in vivo attention. The second study tested individuals using the same in vivo assessment following a 0.30 g/kg dose of alcohol, a 0.65 g/kg dose of alcohol and a placebo. Participants also completed the visual dot probe task in order to measure and compare their attentional bias in a more traditionally implemented task to the novel in vivo approach. Results from the first study indicate that as the novelty of stimuli begins to wane and habituation to neutral stimuli occurs, attentional bias to alcohol-related objects emerges. This attentional bias was shown to be related to drinking habits, where heavier drinkers demonstrated increased attentional bias. The second study in this research found no discernible effect of alcohol consumption on in vivo attentional bias, but did identify a satiating effect of consumption on bias as measured by the visual dot probe task. Additional visual dot probe findings suggest the specificity of the effect of alcohol consumption on attentional bias. Together, these findings help inform whether there is benefit in utilizing an ecological model of measuring attentional bias and how the phenomenon might be measured in laboratory settings in the future.

<div><div><div><p>Increased meal size on a western diet is a major contributor to development and maintenance of obesity. This also leads to decreased sensitivity to the satiating effects of the western diet. Excitation of cells during consumption of a meal in the caudal two-thirds of the nucleus solitary tract (cNTS) in the brainstem are thought to produce satiation and inhibit feeding. Currently, it is unknown how excitation of these cells inhibits feeding. A major obstacle has been the inability to selectively manipulate these cells without affecting intermixed cells that mediate other autonomic functions. We propose a novel approach using inducible, activity-dependent chemogenetics or optogenetics to test whether artificial excitation of cells in the caudal two-thirds of the nucleus solitary tract (cNTS) activated during satiation can reduce food intake and could contribute to preventing or reversing obesity in humans.</p><p>We tested four different mouse models with potential for answering this question: double transgenic mice with cFos-tTA & Tet-O-hM3Dq genes, a single transgenic cFos-tTA mouse with a virally delivered hM3Dq gene injected into the cNTS, a double transgenic mice with the TRAP2- tdTomato genes and double transgenic mice with c-Fos-tTA and ChEF genes. Evidence suggested that clozapine-N-oxide might activate satiation-related cells in the absence of the hM3Dq receptor and this should be taken into consideration for future experiments. All four models had promising aspects for studying feeding as well as serious limitations. These limitations will need to be considered when deciding to use any of these models to study any feeding behaviors, especially satiation.</p></div></div></div>

Previous research on the assessment of pediatric feeding disorders has shown that negative reinforcement (escape) plays a major role in the maintenance of food refusal and that escape extinction (EE) may be necessary in the treatment of severe food refusal. The current study examined the influence of two potential motivating operations (MOs) on escape from bite presentations for 3 children with severe food refusal: (a) noncontingent positive reinforcement (NCR) and (b) food satiation (as a result of enteral nutritional support). The abolishing effects of NCR on negative reinforcement for refusal behaviors were demonstrated in Experiment 1 when escape was allowed for food refusal and in Experiment 2 during demand fading across a hierarchy of bite placements. The interactive effects of NCR and food satiation on negative reinforcement for escaping bite presentations (within a hierarchy of bite placements) were demonstrated in Experiment 3. NCR abolished escape as a reinforcer and food satiation established escape as a reinforcer. The combined MO effects of NCR and food deprivation resulted in decreased refusal behaviors and increased acceptance across all bite placements in Experiment 3 even though escape was allowed. Results extend the existing bodies of literature on the competition between positive and negative reinforcement and the effects of specific biological conditions on escape-maintained behavior. Implications for treatment and future research are discussed.

At present, the Florida Burrowing Owl is being threatened by extensive habitat development throughout their small range in the state. Unfortunately, developers are able to collapse burrowing owl burrows during the non-breeding season and flush the owls from an area. In other areas such as Arizona and British Columbia translocation is being utilized to mitigate the effects of development on burrowing owls. In March 2006, the only translocation of burrowing owls in Florida was conducted by Mosaic Phosphate Company. The purpose of this thesis was to elucidate the effects of translocation on Florida burrowing owls. Topics of research include activity budgets, insect trapping, burrowing owl diet, prey availability, and hatching success for two populations of Florida burrowing owls in Hillsborough and Polk Counties, Florida. Results of this study indicate that translocation has little effect on Florida Burrowing Owl activity budgets. There were significant differences in scanning, time spent in the burrow, and resting between the control and treatment groups (p < 0.05). Though differences in behavior were present between translocated and non-translocated study groups, there was no statistically significant difference (p < 0.025) between the pre-and post translocation study group. Results of the prey availability study indicate that while there are significantly different amounts of arthropods between study areas (p < 0.025), a threshold or satiation point may have been reached at these areas, as trapping results do not match diet results. This satiation point may have been due to cattle dung present at the burrowing owl's breeding areas, which provides a micro-habitat for many prey items. While hatching success was lower for the post translocation group compared to the pre-translocation group, hatching success also was decreased for the control group.This overall decrease indicates that translocation was not the main factor affecting the hatching success of our study groups.

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.

The effect of meal-time exposure to food advertisements (FA) on food intake, subjective appetite and caloric compensation was investigated in overweight/obese (OW/OB) and normal weight (NW) boys (study 1) and girls (study 2). In random order, each participant watched either FA or non-food advertisements (NFA) 30 min after consumption of either a non-caloric sweetened control (CON) or a glucose (GLU) drink. Food advertisements increased food intake only in OW/OB girls. The GLU drink reduced food intake in both girls and boys despite no changes in subjective appetite. Food advertisements did not modify the response to the GLU drink in girls and contrary to the hypothesis they magnified the reduction in energy intake following the GLU drink in boys. In conclusion, FA in a TV program during consumption of a pizza meal by NW and OW/OB boys and girls increased food intake only in OW/OB girls and increased caloric compensation for the GLU drink at meal time in boys but not in girls.

The effect of meal-time exposure to food advertisements (FA) on food intake, subjective appetite and caloric compensation was investigated in overweight/obese (OW/OB) and normal weight (NW) boys (study 1) and girls (study 2). In random order, each participant watched either FA or non-food advertisements (NFA) 30 min after consumption of either a non-caloric sweetened control (CON) or a glucose (GLU) drink. Food advertisements increased food intake only in OW/OB girls. The GLU drink reduced food intake in both girls and boys despite no changes in subjective appetite. Food advertisements did not modify the response to the GLU drink in girls and contrary to the hypothesis they magnified the reduction in energy intake following the GLU drink in boys. In conclusion, FA in a TV program during consumption of a pizza meal by NW and OW/OB boys and girls increased food intake only in OW/OB girls and increased caloric compensation for the GLU drink at meal time in boys but not in girls.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-06-21T20:25:52Z No. of bitstreams: 1 estevaogoncalvesbittar.pdf: 5760202 bytes, checksum: 84b0d72763536df563dc1d4ca2883ef8 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-08-07T19:19:48Z (GMT) No. of bitstreams: 1 estevaogoncalvesbittar.pdf: 5760202 bytes, checksum: 84b0d72763536df563dc1d4ca2883ef8 (MD5) / Made available in DSpace on 2017-08-07T19:19:48Z (GMT). No. of bitstreams: 1 estevaogoncalvesbittar.pdf: 5760202 bytes, checksum: 84b0d72763536df563dc1d4ca2883ef8 (MD5) Previous issue date: 2012-02-24 / A taxa de resposta sofre variações ao longo de uma sessão experimental livre-operante típica. Essas variações são ordenadas, e confiavelmente demonstradas com sujeitos de diferentes espécies, respondendo sob diferentes condições experimentais. Killeen (1995) postulou que as variações na taxa de resposta são uma função da interação entre excitação e saciação, e ofereceu um modelo matemático para essa hipótese. O presente estudo analisa o modelo de Killeen, demonstrando que, embora sólido em seus princípios, ele apresenta algumas falhas em sua implementação. Posteriormente, baseado nos mesmos princípios, é desenvolvido e testado um novo modelo da dinâmica motivacional intra-sessão. Também é demonstrado que, representando a excitação como uma variável com valores entre O e 1, é possível obter um modelo surpreendentemente simples da taxa de emissão de um livre-operante. / Operant response rate changes within the course of a typical free-operant experimental session. These changes are orderly, and reliably demonstrated with subjects from different species, responding under different experimental conditions. Killeen (1995) postulated that the response rate changes are a function of the interplay between arousal and satiation, and offered a mathematical model for this hypothesis. The present study analyzes Killeen's model, demonstrating that, although solid in its principles, it presents some flaws in its implementation. Then, based on the same principles, a new model of within-session motivational dynamics is built and tested. It is also demonstrated that, by representing arousal as a variable that ranges between 0 and 1, it's possible to obtain a surprisingly simple model of free-operant response rate.

We develop a consumption model to analyze the relative importance of time and money for consumer behavior and prosperity. The model is characterized by three situations a consumer may face. Equilibrium conditions are different in each of those situations. At equilibrium A only the time constraint is binding. The appropriate situation is called relative time scarcity. At equilibrium B, relative satiation, the consumer's income constraint is binding at the optimal allocation of time. At equilibrium C, consumers deviate from their optimal allocation of time because of the income constraint. Those consumers face relative money scarcity. We analyze behavioral reactions to changes in prices, disposable income and available time in each of those three situations. It turns out that substitution effects only exist in situations of relative money scarcity - the only situation dealt with in ordinary (i.e. timeless) consumer theory. The absence of substitution effects in situations of relative time scarcity and relative satiation leads us to the conclusion, that the impact of changes in relative prices on consumer behavior is much less important than usually assumed. Another interesting result is that increases in disposable income do not necessarily lead to a gain in prosperity. The effects of changes in disposable income and time availability on prosperity depend on the situation a consumer faces.(author's abstract) / Series: SRE - Discussion Papers