Psychology

Pain conditions occur at an increasing rate alongside people with temporal lobe epilepsy (TLE) and can include chronic headaches, migraines, and neuropathic pain. In order to begin to understand the concurrence, this experiment aimed to investigate the effect of long-term amygdala kindling, a model of TLE, on the affective and nociceptive components of pain in rats. Formalin-induced affective avoidance was investigated using the conditioned place aversion (CPA) test and found aversion in kindled, but not sham rats. Nociceptive behaviours were observed using the formalin test and found a peripheral reduction of pain, that persisted one-week following the last stimulation in kindled rats. Lower activation of c-Fos in the periaqueductal gray was seen in kindled rats, while no changes in protein kinase C δ activation was found. Amygdala kindling contributed to pain sensitivity changes that persisted into the interictal period, and male and female pain trends were found, requiring further investigation.

Author Keywords: affective pain, amygdala, amygdala kindling, formalin, nociceptive pain, periaqueductal gray

Ageism is pervasive and harmful, creating an urgent need to understand how ageist attitudes can be improved. Building on the novel age-conscious student concept, this thesis explored the outcomes of a pilot intergenerational classroom, aimed at reducing ageism, that integrated 13 older community participants into a university-based psychology of aging course alongside 60 younger students. Following course completion, 31 individual interviews (13 community participants,18 students) and one focus group (4 students) were conducted to assess the impact of intergenerational connectivity on ageism and age-consciousness. An iterative collaborative qualitative analysis revealed three major themes regarding participants' experiences with ageism and age-consciousness in the intergenerational classroom: (1) heightened knowledge of ageism, (2) transformed attitudes toward aging and youth, and (3) enhanced personal connection with aging. From these findings, a revised model of age-consciousness is presented, describing three integrative factors that promote positive attitudes toward aging and youth.

Author Keywords: age-conscious student, age-consciousness, ageism, ageism intervention, intergenerational, qualitative

In today's digital era, smartphone use is having a profound effect on family life. There is growing concern about parental phubbing, which occurs when parents ignore their children in favour of using their phones. This study examined how parental phubbing was associated with children's problematic media use (PMU), and problem behaviours (internalizing, externalizing,attention) during middle childhood. The role of the parent-child relationship, measured by closeness and conflict, was also explored given its well-established influence on child development. Participants included 99 parents/guardians of 6-8-year-olds and 87 parents/guardians of 9-12-year-olds. Data on all variables were collected through online surveys. Across both groups, phubbing was associated with children's PMU. Among the 6-8-year-old's, phubbing was also linked to internalizing and externalizing problems. In this age group, parent-child closeness buffered phubbing effects while conflict mediated the relationship between phubbing and children's behaviour. These findings enhance our understanding of parental phubbing within Canadian family contexts.

Author Keywords: Middle Childhood, Parent-Child Relationship, Phubbing, Problem Behaviours, Problematic media use

This study aimed to explore relationships between impulsivity scores, cannabis use, and performance on vigilance, attention, and decision making tasks. We also investigated whether cannabis use related to self-reported risk taking behaviours, including risky driving, openness to engage with cryptocurrency markets, or gambling behaviour. The regular recreational cannabis users had significantly higher impulsivity scores and tendency to use other substances than non-users. The regular cannabis users had better performance efficiency than non-users for hit targets on the vigilance task, but not the other two target trial types. The regular cannabis users made significantly fewer errors than non-users on the verbal Stroop task. There were no significant performance differences on the Iowa Gambling Task between the regular recreational cannabis users and non-users. None of our other hypotheses explorations yielded statistically significant results.

Author Keywords: cannabis, cryptocurrency, gambling, impulsivity, Stroop, vigilance

Two dimension-based models have emerged that capture the high symptom heterogeneity observed in obsessive-compulsive disorder (OCD)—one grouping symptoms by their overt presentation, the other identifying core dimensions of underlying symptom motivations. This paper presents two studies that explore (1) the relationship between these two models, and (2) the stability of the models and dimensions they each represent. Study 1 found that the core dimension motives jointly predicted overall OCD symptom severity, and that each core dimension further predicted unique nonoverlapping overt symptom dimensions. Study 2 demonstrated that despite high instances of item-level symptom change, both models and their respective dimensions were longitudinally stable, with exception to overt symptoms relating to harm/injury/bad luck. Both studies support further consideration of these models as clinical resources and support the candidacy of the core dimensions as endophenotypes for OCD. Results, limitations, clinical implications, and future directions are discussed.

Author Keywords: Core Dimensions, Endophenotype, Obsessive-Compulsive Disorder, Overt Symptoms, Stability, Symptom Models

Stress can significantly affect neurobiological processes crucial for learning and memory. While repeated stress enhances fear memory, it impairs memory retrieval. In most studies, however, stress exposure typically preceded fear and extinction learning. Thus, the impact of previously acquired memories formed before exposure to stress is not well understood. The goal of this thesis is to examine how acute stress impacts the ability to retrieve previously acquired fear memories. The results showed that stress impaired recall of recent fear memories, but stress seven days after conditioning did not affect memory retrieval. Analysis of c-Fos expression revealed increased neuronal activity in the medial prefrontal cortex (mPFC) of rats exposed to stress. Additionally, stress exposure decreased mRNA expression of Reelin, a glycoprotein in the mPFC. Notably, administering recombinant Reelin improved fear memory recall. These findings highlight potential pathways for research and interventions on stress-induced memory impairments.

Author Keywords: c-Fos expression, Fear memory, Medial prefrontal cortex, Memory retrieval, Reelin, Stress

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

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