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Recherche uO, le dépôt numérique de l'Université d'Ottawa, réunit le matériel de recherche et d'enseignement créé par notre communauté universitaire et nos partenaires. Le savoir de l'Université est ainsi disponible à long terme et en accès libre, ce qui lui procure de la visibilité et facilite sa diffusion.

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What happens next? The Long-Term Impact of Cancer Treatment on Memory and Affective Symptoms in Breast Cancer Survivors
(Université d'Ottawa / University of Ottawa, 2026-09-18) Bradley-Garcia, Meenakshie; Sekeres, Melanie J.
Breast cancer is the most frequently diagnosed cancer worldwide, with increasing survival rates heightening awareness of long-term treatment-related effects on cognitive and mental health. Memory impairments are among the most commonly reported and functionally impactful complaints in survivors. However, most memory research relies on laboratory-based tasks that may not capture the complexity of everyday episodic memory, which depends on hippocampal mechanisms supporting the encoding and retrieval of rich contextual information and may be vulnerable to chemotherapy-related neurotoxicity. This thesis examines the long-term impact of breast cancer treatment on cognitive and psychological functioning across four objectives: (1) reviewing mechanisms underlying episodic memory impairment following cancer treatment, (2) characterizing long-term psychological outcomes and their interrelationships, (3) assessing episodic memory using standard and ecologically valid measures over short delays, and (4) evaluating memory for complex naturalistic events using film-based stimuli over extended delays, focusing on central and peripheral details. We recruited Canadian women aged 30-65 years with a history of breast cancer who were at least six months post-treatment and age-matched non-cancer controls. During the first session, participants provided demographic and health information, and completed online questionnaires assessing stress, depression, anxiety, fatigue, and sleep quality. In the second session, participants completed two cognitive tasks to assess episodic memory using a narrative recall and verbal paired associates task, and two questionnaires to assess cognitive workload and perceived episodic and semantic memory abilities. In the final two sessions, participants viewed 40 short film clips and were asked to recall 20 clips immediately after encoding and the remaining 20 after a 7-day delay. Breast cancer survivors reported higher levels of stress, depression, anxiety, fatigue, and sleep disturbance than controls, with each factor being interrelated. Breast cancer survivors recalled fewer verbatim and gist details for the narrative recall task than non-cancer controls, with impairments in gist memory persisting during delayed recall. However, no memory deficits were evident on the paired associate task in breast cancer survivors. Breast cancer survivors reported greater cognitive effort during the story recall tasks, but no group differences emerged for the paired associate task. Survivors also reported greater cognitive effort during narrative tasks and greater subjective memory difficulties. In the film-based task, both groups showed comparable rates of forgetting over time; however, survivors recalled fewer central and peripheral details overall, with specific impairments for object-related and multimodal (spatial, auditory, and event-based) information. The findings highlight the enduring cognitive and psychological sequelae of cancer treatment in breast cancer survivors, which may be partly influenced by the neurotoxic effects of chemotherapy on hippocampal functioning, a brain region critically involved in episodic memory. Although survivors performed similarly to non-cancer controls on standard neuropsychological memory measures, they demonstrated impairments on more complex, ecologically valid memory tasks, suggesting that traditional assessments may underestimate the everyday memory challenges experienced in survivorship. Furthermore, survivors exhibited difficulties recalling both gist-based and episodically rich details of naturalistic events, providing evidence of specific episodic memory vulnerabilities following treatment. Together, these findings support the need for comprehensive survivorship assessments incorporating ecologically valid cognitive measures alongside standard tests and subjective reports to better identify functional impairments and guide intervention strategies.
Pour une nouvelle édition critique de la tragédie Aman d'Antoine de Montchrestien (1604)
(Université d'Ottawa / University of Ottawa, 2026-09-18) Magalhães, Anderson; Frappier, Louise
The Fluid Provenance and Ore Mineralisation History of the Ecton Copper Mine, Central England
(Université d'Ottawa / University of Ottawa, 2026-09-18) Harris, Ryan; O'Driscoll, Brian
Mississippi-Valley type (MVT) ore deposits are significant global sources of lead and zinc. These deposits are the result of relatively low temperature hydrothermal fluids precipitating ore minerals in cavities and veins, typically occurring in regionally-significant ore districts that contain multiple deposits (e.g. Pine Point, Canada; Irish Midlands, Ireland; and Viburnum Trend, USA). The MVT deposits of the South Pennine orefield, central England, are historically important, producing large amounts of lead, zinc, and fluoride, predominantly during the 19th and 20th centuries. Located in this orefield is Ecton Mine, with an extensive history of mining dating back to the Bronze Age. Between 1760 and 1820; the Deep Ecton mine produced over 100,000 tonnes of copper ore before its eventual closure and flooding. The copper ore, mainly chalcopyrite, formed in vertical cylindrical pipes, cross-cutting bedding in the host carbonates. Within the South Pennine orefield, the high abundance of copper makes Ecton anomalous. Many aspects of Ecton mineralization (such as fluid composition, emplacement temperature, and structural controls) remain unclear, particularly within the context of other deposits in the South Pennine orefield. Research on Ecton ore genesis is made difficult by a lack of useful study material; resources were totally exhausted and the site is formally recognized, and protected, as a historical landmark. Working with samples from the Deep Ecton mine, obtained through various museum collections, petrographic, cathodoluminescence, SEM/EPMA, LA-ICP-MS, and sulfur isotope data are used to characterize the fluid provenance and mineralization processes leading to the formation of the Ecton orebody. Analysis of trace elements in calcite reveals that the mineralisation at Ecton was the result of a fluid mixing event, likely between a seawater-derived fluid and a metal-bearing hydrothermal fluid. The sulfur isotope data from this study (avg. -15.9‰) overlap with previously reported values for the South Pennine Orefield, and bacterial sulfate reduction is proposed as the mechanism of sulfur derivation. The samples also contain Ni-rich minerals like gersdorffite, and relatively Ni-rich pyrite (up to 17.5 wt.%), and element mapping shows chemical zoning of Cu, Ni and Co in single crystals of marcasite. These observations demonstrate that the mineralising fluid at Ecton, and possibly the South Pennine Orefield, was enriched in elements not found in abundance in typical MVT deposits. This study also finds that Ecton has characteristics that are comparable to Irish-type deposits (e.g. Cu-As-Ni-Co mineral assemblages, and structural controls), which challenges the classification of Ecton as a classic MVT deposit.
Genetic and Physiological Characterization of Gramillin Sensitivity in Barley
(Université d'Ottawa / University of Ottawa, 2026-09-18) Lakshmanan, Siddharthan; Brauer, Elizabeth
Microbes produce ionophores, metabolites which facilitate ion transport across membranes, to disrupt host membranes and cellular function. Plant hosts can perceive ionophore-based disruption, and some genotypes have developed ionophore insensitivity. The basis of ionophore insensitivity is unclear but could involve avoidance of membrane interaction with the ionophore, ionophore degradation or membrane recovery. Here, we describe the insensitivity of the Lowe barley against the gramillin ionophore, a virulence factor produced by Fusarium graminearum that induces host stress responses which then promote fungal secondary metabolite gene expression during infection. During barley leaf infection, higher F. graminearum trichothecene and culmorin biosynthetic gene expression was observed in gramillin-sensitive barley compared to Lowe. Lowe degrades gramillin to a similar extent as gramillin-sensitive genotypes and can induce callose production and transcriptional reprogramming in response to gramillin. However, gramillin-induced stress responses are smaller in Lowe compared to gramillin-sensitive barley genotypes. At 4 hours after gramillin treatment, only 1,175 genes are differentially expressed in Lowe compared to 3,885 in gramillin-sensitive Leo barley. Gramillin-induced callose production and defense gene induction are smaller in Lowe compared to sensitive genotypes. Inducible stress responses were not required for gramillin insensitivity in Lowe. Together, this indicates that gramillin can disrupt membranes in Lowe to induce stress responses and that Lowe insensitivity is unlikely due to complete avoidance or gramillin degradation. Instead, the toxicity of gramillin is attenuated in Lowe which aligns with lower induction of F. graminearum secondary metabolite biosynthetic genes during infection.
Synaptic Shaping of Cortical Dynamics at Species Specific Scales
(Université d'Ottawa / University of Ottawa, 2026-09-18) Beninger, John; Naud, Richard; Toth, Katalin
Events in the world are structured both spatially and temporally: while brains vary greatly in size across species, they must coordinate neuronal populations in response to shared environmental timescales. How are spatial and temporal structure scalably encoded in cortical dynamics? Individually, synapses show preferential responses to particular temporal patterns of activity enabled by transient changes in connection strength known as short-term plasticity. At a group level, one idea is that sensory stimulation evokes cortical travelling waves which share information between spatially distant neurons and act as a record of the recent past. However, individual synaptic dynamics display a large degree of heterogeneity that is informally separated into classes despite the precise number and properties of such classes being unclear. Moreover, species with larger brains have more neurons distributed over larger spatial volumes: for cortical waves to integrate information from topologically organized receptive fields in different species, they must propagate via mechanisms that scale proportionately. To make sense of this complexity, this thesis leverages modelling spanning from the scale of synapses to networks, as well as machine learning tools, a large open synaptic physiology dataset, and novel experiments performed by collaborating scientists. We present a picture of the cortical microcircuit where synaptic dynamics belong to a nuanced dictionary of functional subtypes and where spatially structured synaptic connectivity encodes local perturbations into cortical travelling waves. In rodent data, we find five functional clusters of synaptic dynamics that partially converge with transgenically defined subtypes. Strikingly, the application of the same clustering method in human data infers a highly similar number of subtypes, supportive of stable clustering. At the network level, our modelling elucidates how cortical synaptic connectivity may selectively encode localized perturbations into transient travelling waves, a prediction consistent with new experimental results from electrical microstimulation of rodent cortical tissue. Crucially, our modelling finds these rodent data consistent with two rival connectivity schemes: one in which perturbations of both human and mouse tissue produce waves of similar scale and a second in which evoked waves propagate more than twice as far in models of human cortex, consistent with a role in species specific scaling of spatiotemporal integration. Taken together, this thesis provides a cross-species account of how the structure of cortical connectivity shapes dynamics across networks including a nuanced dictionary of specific functional subtypes of cortical connections and a falsifiable mechanistic prediction about how neuronal populations of species specific scale may be coordinated in response to shared environmental scales.