Thesis advisor: Gorica D. Petrovich / Learned associations are formed when cues from the environment are paired with biologically important events and can later drive appetitive and aversive behaviors. These behaviors can persist and reappear after extinction because the original learned associations continue to exist. In particular, cues previously associated with food can later stimulate appetite and food consumption in the absence of hunger. Renewal, or reinstatement, of extinguished conditioned behaviors may help explain the mechanisms underlying persistent responding to food cues and difficulty associated with changing unhealthy eating habits. The aim of this dissertation was to determine key components in the neural circuitry mediating renewal of responding to food cues. The main focus was on the ventromedial prefrontal cortex (vmPFC; includes the infralimbic (ILA) and prelimbic (PL) areas) because that region was selectively recruited during context-dependent renewal (Chapter 3). In all of the experiments, the behavior and neural substrates of male and female rats were compared. It was important to examine both males and females because sex differences in context-mediated renewal were recently established: males consistently show renewal responding while females fail to do so (Chapters 2 and 3). The first study in this dissertation examined whether behavioral sex differences were driven by estradiol (Chapter 2) and whether the vmPFC is recruited during renewal responding (Fos induction; Chapter 3). Then, to establish the vmPFC is causal in driving the behavioral responding during renewal in a sex-specific way (Chapter 4), the vmPFC was silenced in males and stimulated it in females. This was accomplished using a chemogenetic methodology, DREADDs (Designer Receptors Exclusively Activated by Designer Drugs). Inhibiting the vmPFC in males blocks renewal responding. Reversely, stimulating the vmPFC in females resulted in renewal of responding. To determine key components of the vmPFC circuitry mediating renewal and whether these were different in males and females the experiments in Chapter 5 examined activation of PL inputs using a retrograde tract tracing combined with Fos detection design. The pathways to the PL from the ventral hippocampal formation (subiculum and CA1), the thalamus (anterior paraventricular nucleus), and the amygdala (anterior basolateral nucleus) were recruited in males and not recruited in females. This lack of recruitment could explain the lack of behavioral responding during renewal for females. Taken together, there are distinct and sex-specific circuitries recruited during context-mediated renewal. The findings from these experiments advanced our understanding of the neural mechanisms underlying sex differences in associative memory and contextual processing. They are also important for our understanding of the resilience of food cue to influence our consumption and diet choices. / Thesis (PhD) — Boston College, 2017. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Psychology.

Aim The experiment proposed to study the effect of sustained visual attention in an effective visual field of 40 degrees, in cued and uncued conditions with different set-sizes. Methods The participants had a normal contrast and visual acuity with normal ocular/general health. The experiments were performed both for central (0 - 20degrees) and peripheral (>20 – 50 degrees) visual fields. The targets were presented with valid and invalid cued conditions in different set-sizes of 500, 1000 and 2000. The targets were Gabor gratings oriented at 90 or 180deg subtending a minimum angle of resolution (MAR) ranging from 1.5-10minarc at 25cm. The spatial frequency of the Gabor ranged from 1- 29cycles/degrees and contrast from 20-100%. The observer had to identify the Gabor with horizontal grating and register the response. The accuracy and the reaction times for the targets were evaluated. Results The central targets had lower reaction times and high accuracy compared to the peripheral targets. There was a significantly increasing eccentricity effect as the targets were displayed much peripherally. It was less with presentation of valid sustained cues but it was not eliminated. The diminishing contrast of the target had a significant increase in reaction times and reduced accuracy. The effect of increasing number of items in the display didn’t show any significant increase in reaction time, i.e. there was no “set-size effect” seen both central and peripheral targets. The valid cues improved the performance with lower reaction times, compared to the neutral cued conditions, in each of the different experiments and resulted in an improved accuracy in both the central and peripheral visual field. Conclusion Visual attention is affected by contrast, target size and spatial gratings. Reaction time is high and accuracy less for low contrast targets, high spatial frequency and larger set-size, except for set-size 2000 in the central field where it was seen that the reaction times were reduced. The effect is consistent in both central and peripheral visual fields. The set-size also has an effect on the reaction times and on accuracy. The effects are more pronounced in the peripheral visual field.

Aim The experiment proposed to study the effect of sustained visual attention in an effective visual field of 40 degrees, in cued and uncued conditions with different set-sizes. Methods The participants had a normal contrast and visual acuity with normal ocular/general health. The experiments were performed both for central (0 - 20degrees) and peripheral (>20 – 50 degrees) visual fields. The targets were presented with valid and invalid cued conditions in different set-sizes of 500, 1000 and 2000. The targets were Gabor gratings oriented at 90 or 180deg subtending a minimum angle of resolution (MAR) ranging from 1.5-10minarc at 25cm. The spatial frequency of the Gabor ranged from 1- 29cycles/degrees and contrast from 20-100%. The observer had to identify the Gabor with horizontal grating and register the response. The accuracy and the reaction times for the targets were evaluated. Results The central targets had lower reaction times and high accuracy compared to the peripheral targets. There was a significantly increasing eccentricity effect as the targets were displayed much peripherally. It was less with presentation of valid sustained cues but it was not eliminated. The diminishing contrast of the target had a significant increase in reaction times and reduced accuracy. The effect of increasing number of items in the display didn’t show any significant increase in reaction time, i.e. there was no “set-size effect” seen both central and peripheral targets. The valid cues improved the performance with lower reaction times, compared to the neutral cued conditions, in each of the different experiments and resulted in an improved accuracy in both the central and peripheral visual field. Conclusion Visual attention is affected by contrast, target size and spatial gratings. Reaction time is high and accuracy less for low contrast targets, high spatial frequency and larger set-size, except for set-size 2000 in the central field where it was seen that the reaction times were reduced. The effect is consistent in both central and peripheral visual fields. The set-size also has an effect on the reaction times and on accuracy. The effects are more pronounced in the peripheral visual field.

Script training is a technique that allows persons with acquired speech and language disorders, such as nonfluent aphasia, to have islands of fluent speech during which they can speak about a topic without pausing or having word-finding errors. Scripts relevant to specific functional situations are written and practiced until memorized. Script training delivered verbally has been effective with clients with aphasia but the role of written cues in the training has not been explored. Therefore the purpose of this study was to compare the effectiveness of script training taught verbally, or verbally with a written script, in persons with aphasia. Three adults, one with Broca’s aphasia and apraxia of speech (AOS), one with Broca’s aphasia, and one with Anomic aphasia were recruited for this study. Participants selected three topics for script training and with the clinician’s help wrote a script and a script prompt for each topic. Scripts were trained one sentence or phrase at a time until 95% repetition accuracy was achieved, then training began for the next script. The effects of two training procedures, verbal only and verbal + written script, were evaluated with a multiple baseline design across training procedures, the order of which was counterbalanced across participants. Maintenance data were collected after each script was mastered and after the study ended. Results revealed that 3 persons with aphasia (PWA) demonstrated mastery of 2-3 scripts each using V+W script training methods, but only 1 participant maintained script accuracy at 16 weeks post-study. More research is needed to explore the role of written and verbal cues on script mastery and generalization.

This thesis explores the temporal analysis of text using the implicit temporal cues present in document. We consider the case when all explicit temporal expressions such as specific dates or years are removed from the text and a bag of words based approach is used for timestamp prediction for the text. A set of gold standard text documents with times- tamps are used as the training set. We also predict time spans for Wikipedia biographies based on their text. We have training texts from 3800 BC to present day. We partition this timeline into equal sized chronons and build a probability histogram for a test document over this chronon sequence. The document is assigned to the chronon with the highest probability. We use 2 approaches: 1) a generative language model with Bayesian priors, and 2) a KL divergence based model. To counter the sparsity in the documents and chronons we use 3 different smoothing techniques across models. We use 3 diverse datasets to test our mod- els: 1) Wikipedia Biographies, 2) Guttenberg Short Stories, and 3) Wikipedia Years dataset. Our models are trained on a subset of Wikipedia biographies. We concentrate on two prediction tasks: 1) time-stamp prediction for a generic text or mid-span prediction for a Wikipedia biography , and 2) life-span prediction for a Wikipedia biography. We achieve an f-score of 81.1% for life-span prediction task and a mean error of around 36 years for mid-span prediction for biographies from present day to 3800 BC. The best model gives a mean error of 18 years for publication date prediction for short stories that are uniformly distributed in the range 1700 AD to 2010 AD. Our models exploit the temporal distribu- tion of text for associating time. Our error analysis reveals interesting properties about the models and datasets used. We try to combine explicit temporal cues extracted from the document with its implicit cues and obtain combined prediction model. We show that a combination of the date-based predictions and language model divergence predictions is highly effective for this task: our best model obtains an f-score of 81.1% and the median error between actual and predicted life span midpoints is 6 years. This would be one of the emphasis for our future work. The above analyses demonstrates that there are strong temporal cues within texts that can be exploited statistically for temporal predictions. We also create good benchmark datasets along the way for the research community to further explore this problem. / text

The ability to make associations between causal cues and outcomes is an important adaptive trait that allows us to properly prepare for an upcoming event. Encoding context is a type of associative processing; thus, context is also an important aspect of acquiring causal relationships. Context gives us additional information about how two events are related and allows us to be flexible in how we respond to causal cues. Research indicates that older adults exhibit an associative deficit as well as a deficit in contextual processing; therefore, it seems likely that these deficits are responsible for the deficit in older adults’ causal learning. The purpose of the current study was to more directly test how associative deficits related to older adults’ contextual processing affect their causal learning. Based on past research, it was hypothesized that older adults would be less likely than younger adults to acquire and use contextual information in causal learning. A causal learning scenario from Boddez, Baeyens, Hermans, and Beckers (2011) was used to test the hypothesis that older adults show deficits in contextual processing in a causal learning scenario. This task examined contextual processing using blocking and extinction. Participants went through eight blocks of trials in which they were exposed to various cues and outcomes. They provided expectancy ratings that indicated how likely they believed an outcome was to occur, and these ratings were used to assess age differences in use of contextual information in a causal learning scenario. As expected, both younger and older adults demonstrated blocking in that they assigned higher causal value to a previously trained target cue (A+) than to another cue (X) that was only presented in compound with cue A later in the task (i.e., AX+). Additionally, when tested in the context where the association was originally learned following extinction training (i.e., A-), the causal value of cue A decreased for all groups, even if extinction training took place in a different context. However, ratings for cue A decreased even more for younger adults whose extinction training took place in a different context when tested in their extinction context.

Game developers strive to maximize immersion and engagement, to emotionally involve the audience in their material. One technique used to increase engagement is the development of new technologies, such as Stereoscopic 3D. Stereoscopic 3D (S3D) creates the impression of depth (stereopsis) in at images by providing additional binocular depth cues, such as convergence and binocular disparity. In this thesis, we explore the effects that S3D has on the player experience in an attempt to uncover design methodologies that can help game developers develop more effective content. Three experiments were designed and conducted to examine the effects S3D has on player experience and game design: i) Engagement in Stereoscopic 3D Games, ii) S3D Depth- Axis Interaction for Video Games: Performance and Engagement, iii) Depth Representation and Player Performance with Depth-Axis Interactivity. We hypothesized that S3D technology would increase immersion and engagement, and new mechanics that exploit the depth axis would be effective. The results of these studies suggest that S3D does not increase user engagement, and is consistent with prior research that suggest the impact of S3D is dependent on the game. They also demonstrate that developers can design unique experiences in stereoscopic 3D, but there may be additional ways to represent depth. The results suggest developers need to adjust the difficulty of their game when including stereoscopic 3D, depending on the interactions of their game. It is our recommendation that developers continue to explore the affordances offered by stereoscopic 3D to create unique experiences, but its inclusion is dependent on their specific game.

The thesis results of two laboratory experiments focusing on the impacts of predation risk, prey density and habitat complexity on predator-prey interaction strengths and predator metabolic rates, complemented by a brief review of the subject. The experimental system used in the first experiment consisted of cladoceran prey, larvae of three dragonfly species (Sympetrum sanguineum, Libellula quadrimaculata, Ischnura cf. elegans) as intermediate predators, and larvae of a large dragonfly species (Aeshna sp.) as a top predator. The second experiment of investigated how predation risk influences metabolic rates of the intermediate predators.

The dissertation thesis focuses on predator ecology in artificial water bodies. Paper I deals with the importance of chemical cues for predator-prey interactions in an aquatic environment. Here, I demonstrate that the ability to detect chemical cues represents a survival benefit for prey species. Paper II points out gillnet methodological bias, which may have subsequent repercussions in field evaluation of a predator's presence and assessment of larger fish abundance in general. Papers III and IV focus on asp Leuciscus aspius spawning grounds. In Paper III, I demonstrate how males maximize their spawning chances by early arrival and in Paper IV, I evaluate the predation pressure of asp prey, Alburnus alburnus, directed on asp eggs.

Par la présente recherche, nous cherchons à soutenir que dans l'éducation philosophique du jeune Nicolas de Cues (entre 1424 et 1431), la tradition albertine de Cologne, diffusée par Heymeric de Campo, a joué un rôle important. Nous pensons aussi que les traces de cette influence de l'albertinisme colonien émergent en particulier dans les écrits épistémologiques du Cusain, en particulier dans le De coniecturis et dans la collection « Idiota ». Nous montrerons que Nicolas de Cues, qui a personnellement connu Heymeric, a eu grâce à lui connaissance des doctrines néo-platoniciennes qui émergent dans le De docta ignorantia et dans les œuvres cusaniennes des années 1440. Contrairement à la perspective historiographique, qui a soutenu une origine byzantine du néoplatonisme de Nicolas de Cues, nous voulons ici montrer une origine colonienne. Nous sommes également convaincus que cette approche méthodologique permet de saisir efficacement la pensée de Nicolas de Cues dans son contexte historique, « 1430-1464 », et topographique, « entre Cologne et Rome ». Elle fournit aussi une clé pour éclairer le rapport entre la philosophie de Nicolas de Cues et certains penseurs modernes : la Cusanus-Renaissance de la première moitié du XXe siècle avait attribué à Nicolas de Cues le titre de « premier philosophe moderne » parce que, contrairement à la tradition scolastique, il aurait placé au centre de ses œuvres le problème de la connaissance humaine, ouvrant ainsi la voie à la révolution subjectiviste de la modernité. Une telle attention pour la connaissance humaine se retrouve également dans la tradition albertine, décrite comme un « illuminisme » au Moyen Age / In this research, we present the hypothesis that the Albertist tradition in Cologne played a significant role in how young Cusanus acquired his philosophical education, in the years from 1424 to 1431, and that the mediator was Heymericus de Campo. We claim that some traces of this albertist influence can be seen above all in Cusanus' gnoseological works, particularly in De coniecturis and in the Idiota collection. Contrary to the historiographical perspective that maintained the hypothesis that Cusanus’ neo-Platonism derived from Byzantine thought, we should like to sustain here that it originated in the school of Cologne and Rhenish philosophy. We are further convinced that this methodological approach provides an efficient tool for interpreting and capturing Cusanus’ thought within its contexts, both historical ( from “1430 to 1464”) and geographical (“from Cologne to Rome”). Moreover, finding traces of Albertism in Cusanus’s education and works offers a new key to interpreting and clarifying his relationship with modern philosophy. The Cusanus-Renaissance in the first half of the twentieth century saw in Cusanus the first modern philosopher because, unlike those of the Scholastic tradition, he was thought to have placed human knowledge at the core of his works, thus paving the way for the modern, subjectivist revolution. From this standpoint, Albert the Great and his “school” seem be be forerunners of the modern tradition, so much so that it was described as “Enlightenment in the Middle Ages