Chan-Reynolds, Michael

ABSTRACT Patients who undergo chemotherapy often complain of a persistent 'brain fog' that can be present up to years after treatment ends. This fog is expressed as marked impairments in areas of learning, memory and mental health. As it stands, researchers have yet to determine the mechanism at fault for these impairments. The present experiment investigates if the neurogenesis that takes place in the subgranular zone of the hippocampus is suppressed as a result of chemotherapy treatment, and results in these impairments. In the following thesis, two models of chemotherapy are used to explore the treatment effects on Long-Evans rats. From here, three behavioural assessments and three measures of immunohistochemical techniques are used to explore the effects of Temozolomide on memory and anxious behaviour. Our findings support the current literature that suggests that Temozolomide suppresses adult hippocampal neurogenesis and results in cognitive and emotional impairments.

Author Keywords: adult hippocampal neurogenesis, Chemotherapy, Chemotherapy-Induced Cognitive Impairment, CICI, Long-Evans rats, Temozolomide

Paramedic data has significant potential for research. Paramedics see many patients every year and collect a wide variety of crucial data at each encounter. This data is rarely used for good reason: it's messy and hard to work with. But like theunderdog character in a classic movie, with a little bit of work and a lot of understanding, paramedic data has significant potential to change the world of medical research. Paramedics throughout the world are involved in research every day, but most of this research uses purpose-built data structures and never takes advantage of the existing data that paramedics create as part of their everyday work. Through a project-based approach grounded in developing a better understanding of the opioid crisis, this thesis will examine the quantity and structure of the existing paramedic data, the complexities of its current design, the steps necessary to access it, and the processes necessary to clean existing data to a point where it can be easily modelled. Once we have our dataset, we will explore the challenges of choosing key metrics by examining the effectiveness of metrics currently employed to monitor the opioid crisis and the influences public health programs and changing policies have had on these metrics. Next, we will explore the temporal distributions of opioid and other intoxicant use with an eye to providing data to support public health in their harm reduction efforts. And lastly, we will look at the effect of fixed- and floating-point temporal influences on intoxicant-related calls with an eye to how these temporal points can affect call volumes. By using this exploration of the opioid crisis, this thesis will show that with a more thorough understanding of what paramedic data is, what data points are available, and the processes needed to transform it, paramedic data has the potential to greatly expand the limits of health care data science into a more precise and more all-encompassing discipline.

Author Keywords: Ambulance, Data Science, Opioid, Overdose, Paramedic, Pre-hospital

Flaked stones tools are the oldest and longest persisting human cultural remains. Some of these tools were made by hominins who were not anatomically or cognitively modern. My thesis uses an eye-tracking device, developed by psychology, to study modern day novice and expert tool making. By comparing these two groups I was able to characterize the behaviours that lead to successful flake making, and furthermore make inferences about the cognitive capacities that hominins would have had to have to have been successful themselves. This study suggests limited engagement of short-term memory and problem solving skills, which is consistent with other studies. However, this study seems to refute the hypothesis that improvements in hand-eye coordination alone account for the rise of flaked stone technology. My thesis also shows that eye-tracking is a fruitful way to study flake making and, based on my research, I propose several future directions of study.

Author Keywords: Eye-tracking, Human Evolution, Knapping, Oldowan, Skill

Near-hand benefits are seen when individuals are able to process targets more quickly, accurately, and with greater precision when a hand is placed near, rather than far from a target. One possibility is that near-hand stimuli recruit visual-tactile bimodal cells. Research reports that placing a hand near a target delayed immediate saccade onset and speeded delayed saccade onset. Study 1 examined saccade onset to targets appearing near a real hand, a realistic fake hand, or a non-hand visual cue. Immediate saccades were facilitated and delayed saccades were slowed with a real hand in the display, in comparison to a fake hand and no-hand. To establish the link between near-hand effects and bimodal cells, Study 2 used repetitive transcranial magnetic stimulation (rTMS) to depress cortical activity in PMd. RTMS did not induce a reversal of interference induced by near-hand, congruent targets. However, a reversal of the hand effect was found in the stimulation group; a real hand in the display may delay immediate saccades and improve delayed saccades post-stimulation. This finding may double dissociate the effect of the real hand from the fake hand and may be inconsistent with the hypothesis that the hand is attracting attention.

Author Keywords: multisensory integration, near-hand effects, PMd, premotor cortex, rTMS, visual-tactile bimodal neurons

Little is actually known about how people cognitively process and integrate information when solving complex mathematical problems. In this thesis, eye-tracking was used to examine how people read and integrate information from mathematical symbols and complex formula, with eye fixations being used as a measure of their current focus of attention. Each participant in the studies was presented with a series of stimuli in the form of mathematical problems and their eyes were tracked as they worked through the problem mentally. From these examinations, we were able to demonstrate differences in both the comprehension and problem-solving, with the results suggesting that what information is selected, and how, is responsible for a large portion of success in solving such problems. We were also able to examine how different mathematical representations of the same mathematical object are attended to by students.

Author Keywords: eye-tracking, mathematical notation, mathematical representations, problem identification, problem-solving, symbolism

Three experiments examined whether semantics is activated automatically by testing whether Arabic digits (e.g., 4), number words (e.g., four), and non-number words (e.g., rat) activate semantics in the absence of central attention within the Psychological Refractory Period (PRP) paradigm. In all three experiments, subjects performed colour discriminations as Task 1. In Task 2, subjects performed magnitude comparisons on digits (Experiment 1) and number words (Experiment 2) and size comparisons on animal words (Experiment 3). Task overlap was controlled by varying stimulus onset asynchrony (SOA). A distance effect arose in Task 2 and yielded underadditive effects with decreasing SOA for both digits and number words, consistent with these notations activating semantics in the absence of central attention, or automatically. A distance effect also arose for animal words, but it was additive with SOA, inconsistent with non-number words activating semantics automatically.

Author Keywords: Automaticity, Central attention, Dual-task, Numerical cognition, Semantics, Word recognition