Browsing by Author "Goodyear, Bradley Gordon"

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    Brain Structural and Functional MRI of Patients with Inflammatory Bowel Disease
    (2019-05-30) Heidari, Faranak; Goodyear, Bradley Gordon; Swain, Mark Gordon; Lebel, Catherine A.; Kaplan, Gilaad G.; Callahan, Brandy L.
    Inflammatory bowel disease (IBD) is a highly-disabling and painful, chronic immune-mediated inflammatory disease (IMID) of the bowel, with an annual incidence and prevalence that continue to rise. IBD diagnosis commonly occurs during young adulthood, and thus greatly impacts an individual’s productivity, leading to substantial economic burden. IBD patients can also experience behavioral symptoms, including mood and sleep disorders, depression and fatigue. While medication and surgery successfully alleviate somatic symptoms, they only partially treat behavioral symptoms. In fact, these symptoms are often considered as emotional reactions to illness and are left untreated, diminishing the quality-of-life of patients and complicating their clinical management. Evidence suggests that these symptoms have a neurological basis, as a result of the impact of inflammatory responses on gut-to-brain signalling pathways. In this thesis, magnetic resonance imaging (MRI) techniques were used to compare the structure and function of brain regions and networks in IBD patients, relative to control subjects. Regions of the basal ganglia exhibited greater volume and decreased susceptibility (a potential indicator of decreased metabolism) in IBD patients. Altered functional connections between these regions as well as connections with motor-related and cognitive areas were also observed. Given the association between the observed regions and symptoms commonly experienced by IBD patients, our studies suggest there is indeed a neurological component to observed IBD-related symptoms. Future longitudinal studies to examine treatment response and specific behavioral domains are warranted, to fully elucidate the interaction between the brain and inflammatory processes in the setting of IBD.
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    Brain Structure and Mental Health in Typically Developing Youth and Those with Prenatal Alcohol Exposure and Postnatal Adversities
    (2019-08-14) Andre, Quinn; Lebel, Catherine A.; Goodyear, Bradley Gordon; Giesbrecht, G. F.
    Mental health problems are linked to brain structural changes, primarily in the limbic system and prefrontal cortex, and commonly emerge in adolescence. Although progress has been made in understanding mental health disorders, there are still gaps in mental health research in pediatric typically-developing cohorts. Research clarifying the underlying mental health-related biomarkers aids in recognition and treatment of mental health problems and builds a foundation for studying other populations, such as those with neurodevelopmental disorders. Prenatal alcohol exposure (PAE) can broadly impact development, including brain structure and mental health. Nearly all individuals with PAE suffer from comorbid mental health disorders, yet little is known about altered brain structure and mental health in youth with PAE. To assess brain structure, structural magnetic resonance imaging (MRI) was used, specifically T1-weighted and diffusion-weighted imaging to measure anatomical volumes and properties of white matter, respectively. Internalizing and externalizing behaviours, negative behaviours directed either internally or externally, respectively, were used to assess symptoms relevant to mental health. In a typical-development cohort, lower mean diffusivity (MD) and higher fractional anisotropy (FA) measures in the cingulum and uncinate were the main underlying biomarkers for internalizing and externalizing behaviours. In the PAE study, youth with PAE showed significantly reduced volumes of the anterior cingulate cortex, superior frontal gyrus, and reduced FA in the cingulum and uncinate compared to controls. Youth with PAE and additional postnatal exposures exhibited similar brain structure to controls (i.e. volumes, FA and MD values), except in MD of the fornix. Both groups with PAE (with or without postnatal exposure) demonstrated higher externalizing behaviours than controls. Between group differences in mental health-brain structure relationships were found in both limbic gray and white matter. Together this research informs brain structure and mental health relationships in two important groups. With an understanding of typical development, a better understanding of the altered trajectories in PAE can be evaluated, and by having a more robust characterization of youth with PAE, improved services and interventions can be provided.
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    Evaluating the utility of advanced MRI methods for monitoring structural changes in demyelinated lesions using two models of multiple sclerosis
    (2019-07-30) Hossain, Md. Shahnewaz; Zhang, Yunyan; Goodyear, Bradley Gordon; Burton, Jodie M.
    The ability to precisely evaluate tissue pathologies and their functional correlates has been an ongoing challenge in patients with multiple sclerosis (MS). MS pathology is complex; however, much of them start from or are mediated by a demyelinating event. In this thesis, I have studied 2 common models of MS: a cuprizone mouse model, and an optic neuritis (ON) human model. I have particularly focused on the investigation of the potential of novel advanced magnetic resonance imaging (MRI) techniques including neurite orientation dispersion and density imaging (NODDI), diffusion tensor imaging (DTI), and MRI texture analysis. The first model evaluates the ability of these methods to assess the time course and regional preference of MS-like pathology following induced demyelination and spontaneous remyelination in mouse brain. The second model tests the feasibility of select imaging measures for detecting structural changes in the optic nerves and correlating clinical measures in acute optic neuritis (AON) as part of a clinical trial of high dose vitamin D. Through a focused study of the corpus callosum over an extended time series, the animal study shows that all MRI metrics have detected the expected changes over the de- and remyelination periods, consistent with histology quantified using a texture method, structure tensor analysis. The NODDI metric neurite density index is specific to myelin integrity, NODDI orientation dispersion index to axonal changes, and texture angular entropy specific to both myelin and axonal changes. Moreover, early de- and remyelination seems to occur in the genu of corpus callosum featuring relatively thin and high-density axons and early demyelination but relatively late repair in the splenium showing large calibre and comparably low-density axons. All NODDI metrics appear to outperform DTI metrics. In a clinical setting, the advanced imaging measures have successfully detected the structural changes in the affected versus non-affected optic nerves and angular entropy correlates with patient disability. Collectively, this thesis suggests that advanced MRI measures are powerful indices of MS-like pathology and could be used clinically for monitoring disease development and treatment responses, deserving further validation.
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    Multimodal fNIRS-EEG Neuroimaging To Monitor Mild Traumatic Brain Injury
    (2024-04-09) Oni, Ibukunoluwa Kolawole; Dunn, Jeffrey Frank; Goodyear, Bradley Gordon; Debert, Chantel T; Federico, Paolo; Dalton, Colin; Neary, Patrick J
    Mild traumatic brain injury (mTBI) has become a major health issue in North America. Approximately 75% of the 1.5 million TBIs that are seen in emergency departments yearly in the US are categorized as mTBI1,2. mTBI results in a variety of symptoms that are difficult to assess and monitor in a hospital emergency department. A number of neuroimaging studies using different techniques have attempted unsuccessfully to identify a consensus on the best approach to diagnosis and monitoring of mTBI. Current neuroimaging methods, when used independently, have demonstrated changes in brain structure and function resulting from mTBI3,4, though findings are highly variable across studies. The complexity and heterogeneity of injury necessitate a combination of methods to better understand the impact of mTBI on the brain and to improve our ability to diagnose and assess recovery following mTBI. In this project, we developed methods to combine simultaneous recordings of functional near-infrared spectroscopy (fNIRS) and electroencephalography (EEG) from mTBI patients. First, we investigated the reliability and reproducibility of the data output fro m both modalities in 15 healthy adults during a resting state task. We found moderate reliability and reproducibility in our fNIRS-EEG data. Next, we investigated the changes in the brain functional activity in 15 adults within 3 months of their mTBI. We compared the data from these patients to 30 normal controls. We investigated the effect of channel selection in fNIRS on the ability to identify groups based on either selecting an individual channel or averaging a group of channels, finding that individual channel selection fared better in identifying differences between groups. In the investigation of differences between the mTBI and controls, We found that task modulated the frequency power of the fNIRS but not the EEG data and that region of measurement influenced the differences between groups. In this thesis, methods were developed to allow for accurate data collection from fNIRS and EEG. These methods can be further expanded to the combination of other modalities in a simultaneous recording. Continued investigation into the combination of modalities will likely play a part in the improvement of recovery methods following an mTBI.
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    Predicting Post-Operative Functional Performance, Treatment Path, and Overall Survival in Glioblastoma Patients based on Tumour Location and Size
    (2016) Li, Luca Yangyang; Frayne, Richard; Stell, William Kenyon; Goodyear, Bradley Gordon; Gobbi, David; Easaw, Jacob Chirakkattu
    Glioblastoma multiforme (GBM) is the most common primary brain malignancy in adults with a median survival of 12-18 months with treatment. Surgical reduction of the tumour volume by 78% or more increases patient life expectancy (further extended by adjuvant radio/chemotherapy). Although GBM surgery focuses on complete removal of the tumour, there is limited evidence supporting the approach, and the question of what effect the extent-ofresection (EOR) has on patient prognosis is frequently asked. Furthermore, extensive surgery in GBM management has been associated with surgically-acquired motor and language deficits. In addition, present subjective appraisals of tumour severity based on location are inconsistent. Working towards an objective grading system with radiological markers has been suggested to improve accuracy. In this thesis, I demonstrate a quantitative approach for assessing tumour severity. These results provide more evidence for tumour anatomical location and size as factors in affecting post-surgical functional performance and predicting clinical response.
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    Training human topographical orientation in a virtual environment: The behavioural and neurological mechanisms
    (2021-12) Umiltà, Alberto Massimiliano; Iaria, Giuseppe; Protzner, Andrea B.; Goodyear, Bradley Gordon; Khun, Simone
    The ability of humans and other animal species to navigate in complex environments is critical to survive. From impairments of this activity a loss of independence derives. It is critical, therefore, to investigate whether navigational abilities are malleable and can improve. The present thesis is aimed at investigating how a 10-day training program can affect spatial abilities, either at the behavioural level or at the neural level in a group of healthy volunteers. The effects of training with a spatial task were tested by comparing data obtained with behavioural tests, Voxel Based Morphometry (VBM), and functional Magnetic Resonance Imaging (fMRI) during a pre-training session and a post-training session. The long-lasting effects of training at the behavioural level were re-tested three months later. The training protocol was based on the Spatial Configuration Task (SCT; Burles, 2014) developed in the Neurolab of the University of Calgary. This task requires correctly reporting the perspective from which two target objects are seen. Before and after training, participants performed 6 spatial tasks, aimed at testing whether the effect of training extended to spatial abilities that had not been trained and 12 standard neuropsychological tests to control for possible improvements attributable to test re-test effects. The results showed a significant improvement in SCT and a nearly significant improvement in the Mental Rotation Task and the Cambridge Face Memory Task. Neither the spatial tasks nor the neuropsychological tests showed changes from pre-training to post-training. At the neural level, the structural changes analyzed by VBM showed that the areas affected by training belonged mostly to the right hemisphere were: R BA1, L BA6, R BA10, L BA18, R BA22, R BA44 The fMRI analysis revealed functional changes in the following areas: R BA1 L BA4 L BA13, R BA19, R BA22, R BA39, R BA40. The results are discussed with reference to the cognitive processes involved in orienting and navigating