There is increasing acknowledgement that problematic interpersonal relationships and negative emotions are key factors in the development and maintenance of various forms of psychopathology. Emotionally Focused Therapy (EFT) for couples centers on changing attachment behaviours as a means to improve distressed relationships by helping partners access underlying emotions and foster positive interactions that promote accessibility and trust. EFT is a highly effective therapeutic approach that encourages the development of adaptive emotion regulation observed in secure attachment. The development and emergence of non-invasive neuroimaging techniques, in particular functional magnetic resonance imaging (fMRI), provides a unique opportunity to investigate neural adaptations underlying successful psychotherapeutic change. Eighteen distressed couples received an average of 23 sessions of EFT, and the resulting functional and structural differences in the neural processing of threat were investigated before and after therapy using MRI methods. Female participants engaged in a stressful task in which they were confronted with the threat of electric shock, while they held their partner’s hand, a stranger’s hand, or were alone in the scanner. Results offered preliminary evidence that EFT can significantly impact emotional dysregulation, promote attenuation of neural threat by their partner, and result in structural change in a key region of emotion circuitry. Moreover, physiological data demonstrated that following EFT for couples, female partners were effectively soothed by their male partners, as demonstrated by decreased cortisol levels.

There is increasing acknowledgement that problematic interpersonal relationships and negative emotions are key factors in the development and maintenance of various forms of psychopathology. Emotionally Focused Therapy (EFT) for couples centers on changing attachment behaviours as a means to improve distressed relationships by helping partners access underlying emotions and foster positive interactions that promote accessibility and trust. EFT is a highly effective therapeutic approach that encourages the development of adaptive emotion regulation observed in secure attachment. The development and emergence of non-invasive neuroimaging techniques, in particular functional magnetic resonance imaging (fMRI), provides a unique opportunity to investigate neural adaptations underlying successful psychotherapeutic change. Eighteen distressed couples received an average of 23 sessions of EFT, and the resulting functional and structural differences in the neural processing of threat were investigated before and after therapy using MRI methods. Female participants engaged in a stressful task in which they were confronted with the threat of electric shock, while they held their partner’s hand, a stranger’s hand, or were alone in the scanner. Results offered preliminary evidence that EFT can significantly impact emotional dysregulation, promote attenuation of neural threat by their partner, and result in structural change in a key region of emotion circuitry. Moreover, physiological data demonstrated that following EFT for couples, female partners were effectively soothed by their male partners, as demonstrated by decreased cortisol levels.

There is increasing acknowledgement that problematic interpersonal relationships and negative emotions are key factors in the development and maintenance of various forms of psychopathology. Emotionally Focused Therapy (EFT) for couples centers on changing attachment behaviours as a means to improve distressed relationships by helping partners access underlying emotions and foster positive interactions that promote accessibility and trust. EFT is a highly effective therapeutic approach that encourages the development of adaptive emotion regulation observed in secure attachment. The development and emergence of non-invasive neuroimaging techniques, in particular functional magnetic resonance imaging (fMRI), provides a unique opportunity to investigate neural adaptations underlying successful psychotherapeutic change. Eighteen distressed couples received an average of 23 sessions of EFT, and the resulting functional and structural differences in the neural processing of threat were investigated before and after therapy using MRI methods. Female participants engaged in a stressful task in which they were confronted with the threat of electric shock, while they held their partner’s hand, a stranger’s hand, or were alone in the scanner. Results offered preliminary evidence that EFT can significantly impact emotional dysregulation, promote attenuation of neural threat by their partner, and result in structural change in a key region of emotion circuitry. Moreover, physiological data demonstrated that following EFT for couples, female partners were effectively soothed by their male partners, as demonstrated by decreased cortisol levels.

Objective: Alcohol use disorder (AUD) remains a leading cause of worldwide mortality and morbidity. The development of neuroanatomical biomarkers offers the potential of novel clinical indicators to guide prevention, early diagnosis, and treatment. Methods: In 76 participants with DSM-5 diagnosed AUD (Mage = 35.75; 51.3% female) and 79 controls (Mage = 34.71; 59.5% female), we utilized magnetic resonance imaging (MRI) to investigate four novel measures: hippocampal and amygdalar subregion volumes, sulcal morphology (SM), and fractal dimensionality (FD). MRI processing, segmentation, and SM and FD quantification were completed using FreeSurfer v6.0 and v7.0, and MATLAB toolboxes, respectively. A significance value of p < .05 was employed for analysis and sex, age, and intracranial volume were included as covariates. Results: Volumes of the right presubiculum, subiculum, and molecular layer head; left lateral and accessory basal nuclei; and corticoamygdaloid transition area were significantly lower in AUD participants relative to healthy controls. Widths of the left occipito-temporal, right middle occipital and lunate, and right marginal part of the cingulate sulci and depth of the post-central sulci were significantly increased in AUD participants relative to controls. Finally, decreased left caudate, left thalamus, right putamen and right pallidum FD and greater inferior lateral and third ventricle FD were observed in AUD participants relative to controls. Each novel measure’s reliability was assessed using test-retest data from the Human Connectome Project and indicated high reliability with median intraclass correlations of .93, .91, .88, and .93 for the hippocampal subfields, amygdalar nuclei, SM, and FD, respectively. Conclusion: These results indicate selectively decreased hippocampal and amygdala subregion volume, increased sulcal depth and width, and differences in FD as promising neuroanatomical biomarkers for AUD. / Thesis / Master of Health Sciences (MSc)

Individuals exposed to alcohol in utero have reduced cortical grey matter volumes. However, the underlying determinants of these reductions have not been investigated exclusively in alcohol-related neurodevelopmental disorder (ARND). Using magnetic resonance imaging scans from 121 participants (57 ARND and 64 controls) aged 8 to 16 years, cortical morphology was analyzed. Results revealed the ARND group had reduced cortical grey matter volumes, but did not differ from controls in cortical thickness. Rather, the cortical abnormalities reflected reductions in global surface area, local surface area reductions in the right occipital-temporal area and right superior temporal gyrus, as well as reduced gyrification. A significant interaction between sex and group was observed, with females showing greater reductions than males in cortical volume and surface area. Results suggest that ARND is characterized by global reductions in cortical surface area and gyrification and females are more vulnerable than males to the teratogenic effects of alcohol.

Individuals exposed to alcohol in utero have reduced cortical grey matter volumes. However, the underlying determinants of these reductions have not been investigated exclusively in alcohol-related neurodevelopmental disorder (ARND). Using magnetic resonance imaging scans from 121 participants (57 ARND and 64 controls) aged 8 to 16 years, cortical morphology was analyzed. Results revealed the ARND group had reduced cortical grey matter volumes, but did not differ from controls in cortical thickness. Rather, the cortical abnormalities reflected reductions in global surface area, local surface area reductions in the right occipital-temporal area and right superior temporal gyrus, as well as reduced gyrification. A significant interaction between sex and group was observed, with females showing greater reductions than males in cortical volume and surface area. Results suggest that ARND is characterized by global reductions in cortical surface area and gyrification and females are more vulnerable than males to the teratogenic effects of alcohol.

Research suggests that the cerebellum is involved in cognition, but its exact role is unclear. The efficiency theory posits that the cerebellum supports processing speed. Other researchers argue that the cerebellum is functionally heterogeneous, and damage to lobes of the cerebellum causes selective loss of cognitive functions. This study sought to determine whether selective impairment in motor, verbal fluency, or processing speed occurred depending on the lobe of the cerebellum that was lesioned. Lesion mapping was used to measure lesion size and volumetric methods were used to measure atrophy in 25 adult survivors of cerebellar tumors. Participants had too a high degree of heterogeneous cerebellar lesions and accompanying atrophy to explore specialization. However, total cerebellar atrophy negatively impacted written and oral processing speed to a greater degree than total cerebellar lesion size. Younger ages at diagnosis and radiation therapy were associated with greater cerebellar atrophy.

Background. Right cerebellar-left frontal (RC-LF) white matter integrity (WMI) has been associated with working memory. Right Superior Longitudinal Fasciculus II (SLF II) WMI has been associated with visual attention. These relationships have held true for neurotypical controls and brain tumor survivors. The current study examined the relationships between RC-LF WMI and processing speed, attention, and working memory. SLF II WMI and visual attention were included as a control tract and task to demonstrate a correlational double dissociation. This study also examined the relationship between the volume of brain regions within the RC-LF network and RC-LF WMI. Methods. Adult survivors of childhood brain tumors (n= 29, age: M=22 years (SD= 5), 45% female) were treated with neurosurgery, and combinations of radiation therapy and chemotherapy. Age- and gender-matched controls (n=29) were also included. Tests of auditory attention span, working memory, visual attention, and processing speed served as cognitive measures. Participants completed a 3T MRI diffusion imaging scan. WMI (FA, RD) and volume served as neuroimaging measures. In the survivor group, partial correlations between WMI and cognitive scores included controlling for type of treatment. Results. A correlational double dissociation was found. RC-LF WMI was associated with auditory attention span (FA: r=.42, p=.03; RD: r=-.50, p=.01), and was not associated with visual attention (FA: r=-.11, p=.59; RD: r=-.11, p=.57). SLF II FA WMI was associated with visual attention (FA: r=.44, p=.02; RD: r=-.17, p=.40), and was not associated with auditory attention span (FA: r=.24, p=.22; RD: r=-.10, p=.62). The relationship between RC-LF WMI and auditory attention span robustly dissociated from working memory and visual attention. In the radiation group, thalamic-frontal segment of RC-LF WMI associated with the volumetric measures of each structure of the RC-LF pathway, whereas in the no radiation group cerebellar-rubral segment of RC-LF WMI associated with the volumetric measures. Conclusions. The current study advances the understanding of structural brain changes following cerebellar tumor resection and treatment because the results show that RC-LF WMI is associated with auditory attention span rather that working memory, provide evidence for a correlational double dissociation, and suggest distinct relationships between WMI and volume based on treatment.

Dans ce mémoire, nous décrivons le travail effectué pour étendre nos connaissances sur les sources d’instabilité instrumentales en imagerie de résonance magnétique, en particulier dans le domaine anatomique par une étude où cinq adultes ont été scannés quatre fois dans la même plate-forme IRM, deux fois avant et deux fois après une mise à niveau importante d’un scanner 3T de Siemens. Les volumes de l’hippocampe droit et gauche de chaque sujet ont été mesurés avec une segmentation manuelle. Nous avons analysé la fiabilité test-retest avant et après la mise à niveau du système d’IRM. Dans le domaine fonctionnel, cinq adultes ont été scannés quatre fois dans la même plate forme IRM deux fois avant et deux fois après la même mise à niveau du scanneur. Les acquisitions du signal BOLD sont faites dans deux différentes résolutions spatiales (2x2x2mm et 4x4x4mm) pour évaluer la sensibilité du signal BOLD sous conditions de haute et basse SNR. Une dernière étude fonctionnelle sur fantôme avait pour but d’étudier la stabilité de la machine pour les images fonctionnelles et détecter les sources de bruit de type machine. La séquence EPI (Echo Planar Imaging) d’écho de gradient à deux dimensions a été utilisée. Des analyses comme le pourcentage des fluctuations et l’analyse de Fourier des résidus ont également été réalisées. Nous résultats indiquent que les différences dans le matériel provenant d’une importante mise à niveau ne peuvent pas compromettre la validité des études structurelles et fonctionnelles faites à travers la mise à niveau du scanneur. Les acquisitions quotidiennes ont permis de suivre l’évolution de la stabilité et de détecter toute source de bruit qui peut détériorer la détection des activations dans les images fonctionnelles. / In this thesis, we describe work we carried out to extend our knowledge on instrumental sources of MRI variability, in both anatomical and functional imaging. The anatomical study involved five adults scanned four times in the same platform MRI twice before and twice after a major update of a 3T Siemens scanner. The volumes of left and right hippocampus of each subject were measured with a manual segmentation. We then analyzed the test-retest reliability before and after updating the MRI system. In the functional study, five adults were scanned four times on the same MRI system twice before and twice after a major hardware update. Blood oxygenation level- dependent (BOLD) acquisitions were made at two different spatial resolutions (2x2x2mm and 4x4x4mm) to assess the reproducibility of BOLD measurements under conditions of high and low SNR. A final functional study using a gel phantom was used to study the stability of the machine for functional images and isolate the sources of noise arising from hardware. Two-dimensional gradient-echo EPI (Echo Planar Imaging) signals were analyzed to assess the percentage variability and Fourier analysis of residual error performed. Our results indicate that the differences in hardware from a major upgrade do not significantly affect the reliability of structural and functional studies spanning a major hardware upgrade. Daily quality assurance acquisitions on phantoms can be used to monitor the stability of the machine, which may aid in the early detection of hardware faults.

Dans ce mémoire, nous décrivons le travail effectué pour étendre nos connaissances sur les sources d’instabilité instrumentales en imagerie de résonance magnétique, en particulier dans le domaine anatomique par une étude où cinq adultes ont été scannés quatre fois dans la même plate-forme IRM, deux fois avant et deux fois après une mise à niveau importante d’un scanner 3T de Siemens. Les volumes de l’hippocampe droit et gauche de chaque sujet ont été mesurés avec une segmentation manuelle. Nous avons analysé la fiabilité test-retest avant et après la mise à niveau du système d’IRM. Dans le domaine fonctionnel, cinq adultes ont été scannés quatre fois dans la même plate forme IRM deux fois avant et deux fois après la même mise à niveau du scanneur. Les acquisitions du signal BOLD sont faites dans deux différentes résolutions spatiales (2x2x2mm et 4x4x4mm) pour évaluer la sensibilité du signal BOLD sous conditions de haute et basse SNR. Une dernière étude fonctionnelle sur fantôme avait pour but d’étudier la stabilité de la machine pour les images fonctionnelles et détecter les sources de bruit de type machine. La séquence EPI (Echo Planar Imaging) d’écho de gradient à deux dimensions a été utilisée. Des analyses comme le pourcentage des fluctuations et l’analyse de Fourier des résidus ont également été réalisées. Nous résultats indiquent que les différences dans le matériel provenant d’une importante mise à niveau ne peuvent pas compromettre la validité des études structurelles et fonctionnelles faites à travers la mise à niveau du scanneur. Les acquisitions quotidiennes ont permis de suivre l’évolution de la stabilité et de détecter toute source de bruit qui peut détériorer la détection des activations dans les images fonctionnelles. / In this thesis, we describe work we carried out to extend our knowledge on instrumental sources of MRI variability, in both anatomical and functional imaging. The anatomical study involved five adults scanned four times in the same platform MRI twice before and twice after a major update of a 3T Siemens scanner. The volumes of left and right hippocampus of each subject were measured with a manual segmentation. We then analyzed the test-retest reliability before and after updating the MRI system. In the functional study, five adults were scanned four times on the same MRI system twice before and twice after a major hardware update. Blood oxygenation level- dependent (BOLD) acquisitions were made at two different spatial resolutions (2x2x2mm and 4x4x4mm) to assess the reproducibility of BOLD measurements under conditions of high and low SNR. A final functional study using a gel phantom was used to study the stability of the machine for functional images and isolate the sources of noise arising from hardware. Two-dimensional gradient-echo EPI (Echo Planar Imaging) signals were analyzed to assess the percentage variability and Fourier analysis of residual error performed. Our results indicate that the differences in hardware from a major upgrade do not significantly affect the reliability of structural and functional studies spanning a major hardware upgrade. Daily quality assurance acquisitions on phantoms can be used to monitor the stability of the machine, which may aid in the early detection of hardware faults.