VictorJuiz/thesis huggingface dataset:
Age-related changes in multisensory self-motion perception

To derive the precise estimates of self-motion necessary to perform mobility-related tasks like walking and driving, humans integrate information about their movement from across their sensory systems (e.g. visual, auditory, proprioceptive, vestibular). However, recent evidence suggests that the way in which multiple sensory inputs are integrated by the adult brain changes with age. The objective of this thesis was to consider, for the first time, whether age-related changes in multisensory integration are observed in the context of self-motion perception. Two research approaches were used. First, I used a simple, simulated driving task to provide visual cues to self-motion and to manipulate the availability of auditory and/or vestibular cues to self-motion (i.e., unisensory versus multisensory conditions). The results revealed that relative to younger adults, older adults generally demonstrate greater differences in performance between multisensory and unisensory conditions. However, the driving task could not disentangle the effects of age-related differences in real-world driving experience from age-related differences in sensory integrative mechanisms. Second, I used an established and highly controlled psychophysical heading perception task to evaluate whether, like younger adults, older adults integrate visual and vestibular cues to self-motion in a statistically optimal fashion. I considered conditions where each of the two cues was presented alone, in combination and congruent, or in combination but indicating conflicting heading angles. Results showed that while older adults did demonstrate optimal integration during congruent conditions, they were comparatively less tolerant to spatial conflicts between the visual and vestibular inputs. Overall, these results may have important implications for the way that older adults perform mobility-related tasks under various perceptual and environmental conditions.

Keywords: Aging
Integration
Motion
Multisensory
Optimal
Perception
Advisor: Campos, Jennifer L
Stories Women Weave: Merging community-based and academic interpretive approaches to style in wood splint baskets in the Upper New York State regional category of the Northeast basketry tradition.

This dissertation explores patterned variability in Indigenous wood splint basket weaving within the Northeastern Woodlands Basketry Tradition. It focuses specifically on the groups that make up the Haudenosaunee confederacy in what is now classified as the Upper New York State regional category. This category has received considerably less attention than the other three regions in Northeastern North America. Basketry has been approached through both community-driven and academic methods, however, both focuse on different aspects of the industry. Academic discussions tend to focus on typologies, origins, and development, whereas community-driven discussions focus more on meaning and the importance of basketry to the communities. Academic researchers and basket making communities alike agree that baskets have the potential to transmit information and merging the information gathered by academic and community-driven research offers a more complete understanding of the Upper New York State basketry tradition. The purpose of this study is to explore the content of these messages present in wood splint baskets through time by using both academic and community-based research as complimentary to one another. The time period under investigation begins in the mid-19th century and continues to the present day. A total of 372 baskets from six museum collections were considered for this study. Block-stamped, hand-painted, and woven designs, common prior to A.D. 1860, were analyzed in terms the visual themes applied to the exterior of the basket. In addition, symmetry analysis was conducted on the themes woven directly into the basket forms on baskets made post A.D.1860. Results of the style analysis revealed decorative elements on both utilitarian and fancy baskets that refer to key cultural concepts that express and communicate themes such as seasonal ceremonies, and the importance of family, the land, and other beings on earlier utility style baskets. These themes do not disappear with the advent of fancy baskets. Rather, the designs woven directly into the fancy baskets are argued as metaphors for some of the same key cultural concepts found in the early baskets that govern the Haudenosaunee people. The designs become integrated in a more subtle way amidst the onslaught of assimilative pressures.

Keywords: basket
Haudenosaunee
northeast
symmetry
women
wood splint
Advisor: Smith, David G.
Gameplay In An Unfamiliar Environment: Novice and Expert Adult Players Encountering Portal For The First Time

This thesis asks how adult video game players encounter an unfamiliar game for the first time by examining their gameplay. Gameplay is â the way a game is actually playedâ (Juul, 2005, p. 83). Players were invited to participate in a recorded gameplay session and share their reflections on their first encounter with Portal, a first-person puzzle video game. Using the video commentary model methodology with an exploratory approach, players reviewed and commented on their gameplay footage immediately following their session using a retroactive talk aloud protocol. These sessions were analyzed, comparing how different players encountered the game, how they identified challenges, and how they created solutions to those challenges. There was a noteworthy diversity in how different players encountered Portal with trends emerging amongst players with similar expertise. Novice players found it more difficult to progress through Portal than expert players. There were differences in times to completion, puzzle comprehension, and assessment of game mechanics when comparing novice and expert players. A continuum of players emerged between those with less gameplay expertise and those with significant gameplay expertise. There were considerable barriers to entry for novice players.

Keywords: Game studies
Information practice
Information studies
Qualitative research
Video games
Advisor: McEwen, Rhonda
Estimation of global land surface evapotranspiration with the consideration of vegetation structural and physiological status from remote sensing

Global land surface evapotranspiration (ET) is a critical constituent of the global energy and water budgets. The average of perennial terrestrial ET accounts for around 60% of precipitation and consumes about 50% of the absorbed solar radiation on the land surface. At least 50% of terrestrial ET is comprised of transpiration – the water efflux through leaf stomata – the variations of which are subject to vegetation status. The structural status of vegetation determines the radiation distribution inside a canopy and the available energy for transpiration and photosynthesis, while physiological status describes the activity of pigments and enzymes associated with the biochemical processes that control photosynthesis and stomata. Currently, the status of vegetation is often underrepresented in terrestrial biosphere models (TBMs) – the principle tools used to simulate terrestrial ET, due to the difficulty of direct measurements of vegetation traits over large scales. Chapter 2 uses ground measured leaf area index (LAI) and clumping index (CI) over nine flux towers to form several upscaling schemes for a TBM and suggests that a two-leaf scheme (TL) is the best upscaling scheme for modelling ET, based on a comprehensive comparison. TL captures the instantaneous features of the radiation distribution and avoids uncertainties in calculating canopy-scale biochemical parameters. Chapter 3 incorporates the ground measured leaf chlorophyll content (LCC) from a forest site into a TBM and establishes a framework to use LCC in TL. Chapter 3 reveals that LCC can work as a robust proxy for the leaf photosynthetic capacity in TBMs, with the estimates of gross primary productivity (GPP) and ET in being considerably improved in spring and autumn. After the site-level study, Chapter 4 uses satellite-derived LAI, CI and LCC to simulate ET and GPP at 124 sites across nine plant functional types distributed globally. Satellite-derived LCC can reduce the biases of ET and GPP estimates at around 60% of the 554 site-years, with the greatest reduction for plant functional types with strong seasonal cycles. This study demonstrates the critical role of vegetation in simulating global ET and GPP, and develops the optimal way to incorporate vegetation structural and physiological parameters in ET modelling.

Advisor: Chen, Jing M
Undergraduate Social Sciences Students' Attitudes Toward Statistics

This study investigated the changes in undergraduate social sciences students’ attitudes toward statistics in an introductory statistics course for social science students. The relationships between students’ attitudes toward statistics and their past mathematics achievement, their statistics outcomes, their sex, and their year of study were also investigated. The Survey of Attitudes Toward Statistics (SATS-36©) was used to collect data on students’ attitudes toward statistics. The study found no significant differences between male and female students’ attitudes toward statistics. Moreover, no significant differences in attitudes were found by year of study of the participants. By the end of their introductory statistics course, students’ attitudes improved for those students with low initial scores regarding their feelings concerning statistics, their competency in doing statistics, their valuing of the subject in their personal and professional lives, their perception of the difficulty of the subject, and their efforts to learn statistics. However, their interest in statistics remained the same. Students’ attitudes-scores dropped for those students with high initial responses regarding their competency to do statistics, their valuing of the subject, and their interest in statistics. Their feelings concerning statistics, their perception of the difficulty of the subject, and their effort to learn statistics remained the same. Students’ past mathematics achievement, their valuing of, and their effort to learn statistics predicted their statistics outcomes by the end of the course. Additionally, students’ interest in statistics predicted their effort to learn statistics and their valuing of the subject by the end of the course, which contributed to their statistics outcomes. The results also revealed that, students’ past mathematics achievement, and their perception of the difficulty of the subject predicted their cognitive competence in statistics, and their cognitive competence predicted their affect toward statistics by the end of the course.

Keywords: Attitudes
Social Sciences
Statistical Literacy
Undergraduates
Advisor: McDougall, Doug
Neural Representations of the Visual World Across Space and Time

A fundamental question of cognition and perception has asked how the human brain represents the local visual environment. Investigations seeking to answer this question have often explored the contributions of spatial information, such as geometry and layout, in forming a holistic percept of the visual world, yet a growing body of work suggests multiple properties may be crucial to the underlying neural mechanisms supporting scene recognition. This dissertation aims to examine the role of common and ubiquitous visual features, described here as geometry and surface properties, in shaping neural representations of the visual environment across space and time. Investigations in Chapter 2 sought to elucidate the weighting of geometry and surface properties in object and scene perception, and demonstrated equal sensitivity in the scene-selective parahippocampal place area for these features within a scene, and greater sensitivity to the surface information of an object, over its geometry. In Chapter 3, the interactions of these properties with goal-directed behaviour and higher-order scene attributes were examined, with results indicating that scene-selective cortex constructs a flexible representation of the visual environment by integrating diagnostic visual information with task context. Following this investigation, Chapter 4 examined these features within the temporal domain, wherein dissociable neural activity patterns emerged demonstrating how these features may diverge across time to influence the time course of scene perception. Together, these results demonstrate that multiple visual properties shape neural representations responsible for successful scene recognition, and these properties interact with goal-directed behaviour, and unfold across time, to influence our perception of the visual world.

Keywords: EEG
fMRI
Geometry
Object
Scene
Texture
Advisor: Cant, Jonathan S
Rapid cAMP signaling regulates the postsynaptic modification underlying synaptic plasticity and memory

Understanding how synaptic structure and function is modulated by synaptic activity is essential for elucidating the mechanisms of learning/memory. Here I propose to elucidate a novel role for postsynaptic cyclic AMP (cAMP), a ubiquitous second messenger, in synaptic plasticity and learning by establishing novel cAMP optogenetic techniques. Strong synaptic activation such as LTP (long-term potentiation) or LTD (long-term depression), induce changes in postsynaptic structures (dendritic spines) in a process called structural potentiation. This process is crucial not only for activity-dependent synapse structural changes but also for functional plasticity such as LTP. We previously revealed that the major cytoskeletal protein actin interacts with the abundant postsynaptic enzyme CaMKIIβ (calcium/calmodulin-dependent protein kinase II β subunit), directly regulating dendritic spine structure during plasticity. Furthermore, we found that it also regulates LTP through the activity-dependent dissociation of the CaMKIIβ/actin complex. However, the detailed signalling pathway for regulating this mechanism during plasticity remains elusive. Pharmacological and genetic manipulation of the postsynaptic cAMP pathway revealed that cAMP signaling is essential for synaptic plasticity and memory. However the rapid spatial and temporal functions are not well known due to the lack of techniques to spatiotemporally control signaling activity. To address how postsynaptic cAMP regulates synaptic plasticity and memory, I established optogenetic approaches to spatiotemporally manipulate cAMP amounts by light from the single synapse to the brain region of freely moving mice. Utilizing this technique, combined with two-photon live imaging, electrophysiology, and mouse behavior assays, I demonstrated a novel role for postsynaptic cAMP modulating structural and functional synaptic plasticity and short-term learning. This proposed research, in particular, the non-invasive light-dependent manipulation of cAMP levels ex vivo, could also serve as valuable tools for elucidating the role of cAMP signalling in a broad variety of research fields.

Keywords: cAMP
FRET
LTP
Memory
Optogenetics
Synaptic plasticity
Advisor: Okamoto, Kenichi
Assessment of Peripheral Microcirculation using Magnetic Resonance Imaging

This thesis describes the development of a new measurement and analysis tool to assess the microcirculation in limb ischemia. Peripheral arterial disease (PAD) is diagnosed by reduced bulk blood flow and blood pressures in the legs. Patients with severe limb ischemia have limited walking ability and may experience rest pain or foot ulceration. PAD can be treated with revascularization for their large-vessel diseases. However, some patients respond poorly to revascularization. It is hypothesized that the microvascular disease component of limb ischemia may contribute to the differential outcome of revascularization. Therefore, this project is motivated to probe peripheral microvascular perfusion and to investigate the related vascular physiology and clinical indications of limb ischemia. A magnetic resonance imaging-based technique, called arterial spin labeling (ASL), was developed to characterize the dynamic perfusion response to brief periods of flow interruption. In a group of healthy subjects, the technique captured the changes of calf muscle reactive hyperemia with respect to the different durations of flow interruption, reflecting the microvascular function in regulating perfusion for different amounts of metabolic stresses. In addition, the technique also captured the differences between patients with PAD and healthy subjects in the dynamic characteristics of reactive hyperemic responses. Next, a quantitative physiological model, incorporating the influences of arterial stenoses and microvascular dysfunction, was established to facilitate the physiological interpretation of ASL reactive hyperemia. Model-derived perfusion indices were compared between subject groups. Patients were found to have higher arterial resistance and lower microvascular sensitivity to hypoxia than the healthy subject group. Finally, the perfusion measures were compared with symptom severity and functional outcome 6-month following successful endovascular revascularization in a cohort of patients. Measures of arterial resistance were related to the manifested severity, whereas the microvascular sensitivity index appeared to differentiate prognosis following revascularization. Overall, this thesis improved the ASL method to assess peripheral muscle perfusion and demonstrated the clinical relevance of perfusion measures to symptom severity and revascularization outcome of PAD for the first time. A future study with a larger patient population and longer follow-up period will be required to confirm the current findings.

Keywords: Arterial Spin Labeling
Microvascular Dysfunction
Perfusion
Peripheral artery disease
Reactive Hyperemia
Revascularization
Advisor: Wright, Graham A
Decolonizing Narratives:Kittitian Women, Knowledge Production and Protest

Abstract The thesis acknowledges how women contest domination and challenge us to re-examine the subjects of our history. It centers the stories of 21 African women, who remember a popular uprising in St. Kitts in 1935. Their stories explore how these embodied narrators reconstruct a defining moment in the islandâ s history for insertion into the gaping holes of history that had been left for the imagination, conjecture, and a hegemonic discursive shaped by archival records. Their stories are worth remembering, demand examining and not just to be recorded for posterity. They must be accorded equal value as academic knowledge. The use of storytelling as a methodological approach introduces the Kittitian language to text, removes the burden of colonized linguistic syntax and grounds the epistemological context of the findings and analysis. It provides new evidence of the invasiveness of coloniality and how it interlocks with Caribbean rebel consciousness to usurp decolonial exertions, discursively and institutionally. The work does not claim to provide a representative sample of the hundreds of protestors in 1935, nor do the women speak for all the citizens who were impacted by the social unrest. It questions the processes that normalize the silencing of valuable knowledge that can only be found in the language and memories of subjugated populations. Finally, this study reconstitutes the tellers as knowledge producers, decolonizes their womanhood, and depathologizes the resistance movement. It focuses on how these culture bearers remember the protest and how they reconstruct themselves in relation to the historical event and how they reconstitute their subjectivities through their understanding of what the protest meant for themselves, their families, and communities. The study has implications for further research and knowledge production designed to decolonize Caribbean histories, to accelerate the process of healing the psychological scars and other residual effects of colonization and attests to the resilience of cultural memory. Keywords: Caribbean cultural forms, womanism, feminism, indigenous research, decolonization, liberation, knowledge production, historiography, social justice education

Keywords: decolonization
feminism
indigenous knowledge
liberation
oomanism
womanism
Advisor: Wane, Njoki
Developing and using a head-mounted miniature microscope to investigate memory formation in a mouse model of Alzheimer's Disease

Alzheimer's Disease (AD) is characterized by progressive memory loss. Results from many experiments suggest AD begins as a disease of synaptic dysfunction. However, how synaptic dysfunction translates into circuit dysfunction and, ultimately, memory impairment is entirely unknown. To address the circuit-level dysfunction in AD, I developed a miniature fluorescent microscope that can be mounted on the head of a behaving mouse. We showed this mini-microscope is capable of imaging hundreds of neurons in the CA1 region of the hippocampus, and with minor modifications, also in deeper brain structures and in two colour channels. To investigate the circuit dysfunction in AD, we used transgenic mice designed to model AD in humans. These TgCRND8 mice (referred to as AD mice) express human familial AD genes and similarly develop memory impairments. As expected, we showed that AD mice have robust memory deficits in a contextual fear conditioning paradigm, in which mice were trained to associate an aversive stimulus with a context. Imaging data from our mini-microscope showed that compared to control mice, CA1 cells in AD mice were hyperexcitable and contained less information related to memory recall. Moreover, cells from AD mice showed a deficit in coordinated activity, suggesting that these mice are impaired in pattern completion, a process important in recalling hippocampal-dependent memories. Previous studies suggest that AD mice have excessive endocytosis of GluA2-containing AMPAR, which accounts for their synaptic dysfunction. We found disrupting GluA2 endocytosis using an interfering peptide (TAT-GluA2\textsubscript{3Y}) before training was sufficient to rescue the memory and circuitry deficits in AD mice. Moreover, we showed disrupting GluA2 endocytosis during a reminder three days after training also restored memory. These results argue that AD mice still retain some aspect of the memory days after training, and that strengthening this weakened memory allowed mice to recall it. In conclusion, I developed and used a novel calcium imaging method to investigate the circuit dysfunction in a mouse model of AD. Using this tool, I revealed an important link between the synaptic and circuit deficits in AD mice. These findings may have important implications for designing the next generation of tools and therapies for AD.

Keywords: Alzheimer's Disease
Calcium imaging
Fear conditioning
Hippocampus
Memory
Pattern completion
Advisor: Josselyn, Sheena A