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Maladaptive fear can develop when nonthreatening stimuli are misinterpreted as dangerous. While fear extinction has been extensively studied, organisms can also learn safety through relief learning, in which cues signalling the termination of an aversive event acquire positive value. Although the medial prefrontal cortex (mPFC) is implicated in regulating responses to threat and safety cues, its role in relief learning remains unclear. In Experiment 1, I validated a relief conditioning paradigm in rats and demonstrated that relief-conditioned animals froze significantly less than fear-conditioned animals during retention. Experiment 2 revealed that relief learning selectively activated the prelimbic cortex (PrL). In Experiment 3, chemogenetic inhibition of the PrL reduced freezing across tones, supporting a causal role in relief expression. Experiment 4 demonstrated that extended training produced more stable and pronounced reductions in freezing than a one-day protocol. Together, these findings identify PrL circuits as key contributors to relief learning.Keywords: Maladaptive fear, relief learning, fear conditioning, medial prefrontal cortex (mPFC), fear extinction, rat model, behavioural freezing, Fos expression, neural circuitry, conditioned stimuli, aversive stimuli, neuroimaging.

Author Keywords: Conditioned stimuli, Fear condtioning, Maladaptive fear, Medial prefrontal cortex, Neural circuitry, Relief learning

The neuronal ceroid lipofuscinoses (NCLs), commonly known as Batten disease, are a family of fatal neurodegenerative disorders that primarily affect children. Several subtypes of NCLs have been reported, each being caused by a mutation in a distinct ceroid lipofuscinosis neuronal (CLN) gene; this results in aberrant lysosome function and the accumulation of lipoprotein aggregates (known as ceroid lipofuscin) within cells. Several innate cellular pathways exist to alleviate the stress caused by the buildup of aggregates. The endoplasmic reticulum (ER) is an essential organelle in this process because it is responsible for maintaining cellular homeostasis through protein production, quality control, and regulating several signalling pathways. The unfolded protein response (UPR) consists of several conserved pathways devoted to attenuating ER stress caused by an accumulation of misfolded proteins or aggregates; at the center of this stress response is GRP78, a molecular chaperone that binds to misfolded proteins to facilitate proper folding. The social amoeba Dictyostelium discoideum is an excellent model system for studying NCLs as it encodes more CLN-like proteins when compared to other classical model organisms (e.g., yeast, worm, fruit fly). In this study, D. discoideum was used to elucidate the effects of ER stress and build an understanding of how cells cope with increased stress. Beyond this, ER stress in D. discoideum models for CLN3 disease and CLN5 disease were evaluated. First and foremost, during the induction of ER stress by tunicamycin, there was an increase in intracellular and extracellular amounts of Grp78 accompanied by an increase in stress-related changes to the ER. Furthermore, models of CLN3 disease and CLN5 disease displayed increased amounts of Grp78 as well as a disrupted ER morphology. Interestingly, wildtype D. discoideum, AX3 cells, treated with tunicamycin displayed a similarly disrupted ER when compared to CLN models. Finally, when subjected to tunicamycin-induced ER stress, these NCL models displayed a trend towards increased Grp78 amounts, however, these cells appear to have a reduced sensitivity to tunicamycin-induced stress compared to wild-type cells. In summary, this study highlights D. discoideum as a model for studying ER stress through the conserved role of Grp78 in the stress response and concludes that an aberrant ER stress underlies the pathology of the NCLs.

Author Keywords: Batten disease, Dictyostelium discoideum, ER stress, GRP78, neuronal ceroid lipofuscinoses (NCLs)

Lake Huron's food web has experienced drastic changes in response to multiple stressors including declines in offshore productivity, decreased trophic transfer efficiency and a transformation of the benthic food web. However, how these changes have affected the diets and isotopic niches of predatory fish is largely unexplored. My diet study analysed stomach contents from five predatory fish species (lake trout, lake whitefish, chinook salmon, rainbow trout, and walleye) from the Ontario waters of Lake Huron. My isotopic study focused on lake trout and lake whitefish, based on community concerns that recovering lake trout are competing with or consuming lake whitefish. By contrast, I found that lake whitefish were a minimal component of lake trout diets, and the diet and isotopic overlap between these two species was low overall, but varied regionally. Both the dietary and isotope analyses reflect the high regional diversity of energy sources used by predatory fish.

Author Keywords: Food web, Isotopic Niche, Lake Huron, Predator-prey, Regime shift, Regional Energy Sources

This thesis demonstrates how the proper application of theoretical archaeological and osteological methods to archival documents can be both illuminating and vital to create a fuller understanding of those who have been historically silenced. By performing an archival analysis informed by an archaeological background, the first four volumes of the Registers of Liberated Africans from Freetown, Sierra Leone are "excavated." In addition to demographic data, four categories of analysis are presented, including Types of Illness and Symptoms, Types of Trauma, Types of Injury and/or Illness, and Multiple Symptoms and Illness. This data was collected during participation in a much larger transcription project using a unique methodology. The following analysis was conducted using a collection of interdisciplinary theories, including theoretical osteoarchaeology, practical osteology, medical anthropology, archival and linguistic analysis and numerical presentation. Discussions include the frequency of diseases, slave ships and barracoons as disease environments, potential causes for common injuries, the difficulties and evolution of medical language, and the limitations of both archival and archaeological work for medical and trauma investigation. While both archival and archaeological methods miss key information, using them in tandem offers a more complete view of a historical person and their life experiences.

Author Keywords: Archive, Disease, Liberated Africans, Osteoarchaeology, Sierra Leone, Trauma

Animal migration is defined as the seasonal movement from one independent and non-overlapping range to another. Understanding how and why animals migrate is important not only to understand their life history processes but also for informing other important ecological processes such as the spread of wildlife disease and habitat alteration. Animal migrations have been impacted by human activity with instances of complete loss of migrations in human-altered areas. Understanding the drivers of migration can help predict responses to future environmental changes and potentially help conserve these phenomena. Seasonal movements of white-tailed deer (deer; Odocoileus virginianus; Zimmerman, 1780) have been linked to seasonal changes in environmental conditions that impact their ability to find food resources and risk of predation. The human shield hypothesis posits that prey species will select habitat close to people to use predator fear of humans to protect themselves from predation. Using global positioning system (GPS) collars, we examined the onset of deer migrations and assessed how environmental variables including snow, temperature, and plant biomass influenced migration departure dates using time-to-event models. We compared deer locations to data from GPS collared coyotes (Canis latrans; Say, 1823) within the same study area to explore daily space-use differences and examine if deer migrations were food or predation-risk driven using generalized linear mixed effects regression models. We found substantial annual and individual variation in deer migration dates. Snow depth was the strongest and most consistent predictor of deer migration, with individuals departing earlier with greater snow depth. Our regression analyses showed that deer selected for habitats closer to and with greater density of anthropogenic structures than coyotes at all times. After removing the animal locations close to areas with active supplemental feeding, these effects were diminished showing no differences in proximity or density of structures. Overall, we found more support for a food driven migration rather than a predator driven human shield. With the reduction in natural food caused by snow cover, we suggest that supplemental feeding is likely influencing the use of wintering areas by deer. The high proportion of deer migrating to human developed areas with supplemental feeders highlights the need for continued research into the impacts of human activity on animal behaviour.

Author Keywords: coyote, human shield, migration, supplemental feeding, white-tailed deer

With wide applications ranging from quantum communication and metrology to biomedicine, single photon sources in solid-state hosts have become a major area of study. Here, we focus on three applications: nanothermometry, optically detected magnetic resonance (ODMR), and second order autocorrelation. We present novel statistical and machine learning (ML) approaches to extract information from experimental and simulated data and benchmark these methods against traditional inference-based statistical approaches. We found that compared to traditional inference-based methods ML algorithms can: i) predict temperatures at the nanoscale with greater accuracy and with less calibration points than traditional fitting methods; ii) identify the resonance peaks in ODMR spectra with factors ~1.3x and ~4.7x better accuracy and resolution and achieved equal or better performance with ~5x less data; and iii) have the potential to parse second order autocorrelation data more efficiently. ML algorithms are thus powerful tools for quantum sensing techniques.

Author Keywords: colour centers, machine learning, nanosensing, nanothermometry, optically detected magnetic resonance, second order autocorrelation

Freezing of gait is a debilitating symptom affecting individuals with Parkinson's disease. Emerging evidence suggests freezing may represent a global motor control deficit beyond gait. We investigated freezing episodes in the upper limbs using spatially-constrained reaching tasks known to elicit freezing of gait. Fourteen people with Parkinson's disease and 13 controls completed reaching tasks under three spatial conditions with varying backgrounds. The tunnel condition produced the greatest kinematic disruptions. Despite people with Parkinson's disease showing significantly longer movement times and slower speeds, they were less accurate in their movements, suggesting observed differences reflect genuine motor control deficits rather than speed-accuracy trade-offs. The tunnel's narrow spatial constraints challenge the motor system's ability to maintain coordinated movement trajectories, with people with Parkinson's disease exhibiting increased trajectory variability. These findings demonstrate that freezing-like episodes extend beyond gait, supporting the hypothesis that freezing represents a global motor phenomenon in Parkinson's disease.

Author Keywords: freezing of gait, motor control, Parkinson's disease, reaching, upper limbs

Freezing is a debilitating phenomenon that reduces quality of life for people withParkinson's disease (PwPD). This study tests the hypothesis that: 1) freezing is linked to executive dysfunction; 2) freezing is a global motor phenomenon, not limited to gait. We compared 14 PwPD to 16 controls. Several aspects of executive function were measured using pro- and anti-saccade tasks under gap and overlap timing conditions, where the gap effect is defined as the reduction in saccade latency associated with the removal of fixation before target presentation. As predicted, results showed larger anti-saccade gap effects in PwPD with than without FOG, and that the pro-saccade gap effect predicted FOG severity in PwPD with FOG. PwPD also demonstrated impaired performance on reaching and walking tasks designed to elicit freezing. These findings strengthen the evidence that executive dysfunction, measured by saccade tasks, is linked to freezing in PwPD.

Author Keywords: executive function, eye movements, freezing of gait, freezing of upper limbs, Parkinson's disease

It is widely believed that basic mental processes involved in skilled reading are automatic in the sense that they occur without intention. Evidence that reading occurs without intention comes from the observation that the meaning of a colour word (e.g., "red") affects the time to name the ink-colour of the word in the Stroop task. Evidence also suggests that non-colour words (e.g., house) interfere even though they are irrelevant to the colour naming task. The present study examined which reading processes are triggered without intention in the non-colour word Stroop task. One hundred and twenty skilled English readers completed both a reading aloud task and a colour naming task. In order to identify the reading processes triggered without intention, three psycholinguistic variables were examined, lexicality, word frequency, and neighbourhood density. The findings suggest that processing up to and including the activation of orthographic lexical representations occurs without intention and that intention is required to activate all subsequent reading processes.

Author Keywords: Attention, Reading, Stroop Effect, Visual Word Recognition

Positive coaching techniques are gaining prominence in the sport of Gymnastics. Coaches are focusing on positive reinforcement, encouragement, and constructive feedback rather than relying solely on traditional, more authoritarian coaching methods. Furthermore, technology is being used to enhance coach-athlete relationships. Video analysis tools and performance tracking software allow for more detailed feedback and communication between coaches and gymnasts. Previous research has shown that sensory feedback, and physical cues and guidance impact both motor learning and motor skill performance. Spotting is a form of physical guidance (touch) that may be used by gymnastics coaches during both the learning phase of a skill and during performance, even after mastery. This research has examined whether and how spotting with touch influences the athlete's skill performance and confidence. The current study explored how spotting affects both skill performance and self-confidence of participants as they performed a basic skill (a backward jump onto a specified target) they have already mastered. We asked Intermediate-level gymnasts to perform a backward jump from height under two levels of landing difficulty, while being spotted with and without touch. Their confidence was measured in each condition using a brief survey. The timing, accuracy and precision of their landing was measured from video recordings of their performance. We evaluated the relationship between touch and skill performance to determine if it is affected by athlete self-confidence. It was hypothesized that physical guidance in the form of spot with touch would improve the accuracy and precision of the jump landing and that athletes would report higher levels of self-confidence in the touch versus no touch condition. We found no significant differences in skill performance and landing stability as assessed by rate of force development and peak force. We found that participants reported significantly higher levels of self-confidence when receiving spot with touch in the easy landing condition.

Author Keywords: gymnastics, physical guidance, self-confidence, skill performance, spotting, touch