Life Sciences Commons^™

Assessing Cognition In A Mouse Model Of Alzheimer’S Disease, Justin B. Mels

Electronic Thesis and Dissertation Repository

A major challenge in behavioural testing of Alzheimer’s disease (AD) mouse models is a low degree of standardization and translatability of tasks to humans. Bussey-Saksida touchscreen systems employ numerous tasks allowing for assessment of advanced cognitive function in mice using paradigms similar to those used in humans. This system can be used to assess cognitive deficits in dementia.

Our study focused on testing visual discrimination, cognitive flexibility and attention of the APP/PS1 familial AD mouse model longitudinally to assess behavioural changes related to cognitive decline. Surprisingly, APP/PS1 mice did not demonstrate impairments in the 5-Choice Serial Reaction Time Task, which …

Comparative Study Of Beat And Temporal Pattern Perception In A Songbird, Brendon Samuels

Electronic Thesis and Dissertation Repository

When humans listen to musical rhythms they sense a beat, the regular pulse that one might tap their foot to. Much about the functions, evolution and neural substrates of beat perception remains unclear. Research has considered whether other species perceive beat, yet more empirical data is needed. Songbirds produce learned rhythmic vocalizations, but can they perceive a beat? To answer this question, I developed a behavioural task that tested whether humans could discriminate rhythms that contained or lacked a beat. I applied an equivalent procedure to test European starlings. I found that humans learned the task with minimal instructions, but …

Characterizing The Cognitive And Emotional Effects Of Delta-9-Tetrahydrocannabinol In Distinct Hippocampal Sub-Regions, Dinat Khan

Electronic Thesis and Dissertation Repository

The objective of this study is to determine the potential differential effects of THC in the DH or VH sub-regions, as well as the upstream effects on PFC neuronal activity and oscillations. Rodents used for electrophysiology were infused with THC or vehicle in the DH or VH regions, combined with PFC recordings. Additionally, a battery of behavioural paradigms was performed. Deficits in short-term memory when THC was infused into both regions was observed, however working memory was impaired with VH infusions only. This could be due to THC-induced dysregulation in the PFC, as beta oscillations were significantly decreased selectively in …

Working Memory And Falls Risk In Older Adults: An Event-Related Potential Study, Yee (Michelle) S. Wong

Electronic Thesis and Dissertation Repository

BACKGROUND: The aging population is rapidly increasing, where currently in North America, the population of older adults (ages 60+) outnumbers the population of children. Falls are a major concern for older adults and their quality of life. Cognitive impairment has been shown to be declined in older adults at-risk for falls, but working memory has not been thoroughly investigated within this population. PURPOSE: To examine differences in Non-Fallers, Moderate Risk for Falls, and Fallers in a working memory task using electroencephalography (EEG). METHODS: Older adults (n=44, female=27) aged 60 – 80 years (m=68.8, SD=4.7) completed two sessions. The first session …

Dopaminergic Medication Decreases Motor Impulsivity On The Go/No-Go Task In Parkinson's Disease, Xue Qing Yang

Electronic Thesis and Dissertation Repository

Parkinson’s disease (PD) is characterized by resting tremor, rigidity, and bradykinesia. Dopaminergic medications treat motor symptoms, but have complex effects on cognition, including impulse control. Impulsivity is multifaceted in nature. Motor impulsivity involves inability to withhold prepotent, automatic responses whereas cognitive impulsivity refers to increased risk-taking and reward-seeking. We anticipated that dopaminergic therapy would decrease motor impulsivity. We employed the Go/No-go paradigm to assess motor impulsivity. PD patients were tested on and off their dopaminergic medication. PD patients on medication had a significantly higher proportion of Go Timeouts (i.e., Go responses not completed by the 750 millisecond deadline) compared to …

Assessing Cognitive Function In Chronic Sport-Related Head Impacts And Aging, Danielle Brewer-Deluce

Electronic Thesis and Dissertation Repository

Healthy normal aging and cumulative head trauma (concussion and subconcussion), can influence cognition independently and concomitantly leading to substantial late-life cognitive impairments (e.g., as seen in increased rates of dementia). With this as motivation, this dissertation explores three aspects of aging, head injury and cognition using the Cambridge Brain Sciences (CBS) cognitive battery (www.cambridgebrainsciences.com).

Study 1 (Chapter 2): Concussion-specific testing combines assessments from multiple domains to evaluate a variety of functions. While clinically relevant, their succinct nature limits the amount of cognitive information available. Eighteen male football athletes were examined at baseline using the Sport Concussion Assessment Tool (SCAT) 3, …

Role Of The Dorsal Striatum In Learning And Decision Making, Nole M. Hiebert

Electronic Thesis and Dissertation Repository

The striatum, the input region of the basal ganglia, has been shown to mediate many cognitive functions. The striatum itself can be functionally segregated into dorsal (DS) and ventral striatum (VS). For more than 60 years, DS has been reported to mediate stimulus-response learning, though evidence has been accruing pointing to a role in decision making. These literatures have been growing independently and an aim of this thesis was to bridge these two bodies of knowledge. We directly investigated the role of DS in stimulus-response learning versus decision making using functional magnetic resonance imaging (fMRI) in patients with Parkinson’s disease …

A Role For The Somatosensory System In Motor Learning By Observing, Heather R. Mcgregor

Electronic Thesis and Dissertation Repository

An influential idea in neuroscience is that action observation activates an observer’s sensory-motor system. This idea has recently been extended to motor learning; observing another individual undergoing motor learning can promote sensory-motor plasticity as well as behavioural changes in both the motor and somatosensory domains. While previous research has suggested a role for the motor system in motor learning by observing, this thesis presents a series of experiments testing the hypothesis that the somatosensory system is also involved in motor learning by observing.

The experiments included in this thesis used force field (FF) adaptation as a model of motor learning, …

Object Processing In The Medial Temporal Lobe: Influence Of Object Domain, Anna Blumenthal

Electronic Thesis and Dissertation Repository

We live in a rich visual world, surrounded by many different kinds of objects. While we may not often reflect on it, our ability to recognize what an object is, detect whether an object is familiar or novel, and bring to mind our general knowledge about an object, are all essential components of adaptive behavior. In this dissertation, I investigate the neural basis of object representations, focusing on medial temporal lobe (MTL) structures, namely, perirhinal cortex, parahippocampal cortex, and hippocampus. I use what type of thing an object is, or more specifically, the broader category (e.g., “face” or “house”) or …