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.

Since the development of magnetic resonance imaging (MRI), there have been many novel advances in our understanding of brain structure and function. More recently, functional MRI has revealed networks of spatially isolated brain regions with temporally correlated activity, forming resting state networks. Research has long shown that mindfulness can produce psychological improvements. A new wave of research is demonstrating how mindfulness is associated with alterations in these brain networks. The current thesis examined changes in patterns of functional connectivity associated with scores from a commonly used mindfulness questionnaire in three resting state networks: the default mode network, the central executive network, and the salience network. Independent component analysis data from 32 healthy participants revealed that mindfulness is associated with altered patterns of functional connectivity in all three networks. For example, decreased connectivity was observed in the precuneus in two of the networks, a region associated with mind wandering. This suggests that mindfulness has a physiological influence on the resting state functional connectivity of the brain that coincides with the underlying principles of mindfulness. / May 2017

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.

Artifacts caused by head motion are a substantial source of error in fMRI that limits its use in neuroscience research and clinical settings. Real-time scan-plane correction by optical tracking has been shown to correct slice misalignment and non-linear spin-history artifacts, however residual artifacts due to dynamic magnetic field non-uniformity may remain in the data. A recently developed correction technique, PLACE, can correct for absolute geometric distortion using the complex image data from two EPI images, with slightly shifted k-space trajectories. We present a correction approach that integrates PLACE into a real-time scan-plane update system by optical tracking, applied to a tissue-equivalent phantom undergoing complex motion and an fMRI finger tapping experiment with overt head motion to induce dynamic field non-uniformity. Experiments suggest that including volume by volume geometric distortion correction by PLACE can suppress dynamic geometric distortion artifacts in a phantom and in vivo and provide more robust activation maps.

Artifacts caused by head motion are a substantial source of error in fMRI that limits its use in neuroscience research and clinical settings. Real-time scan-plane correction by optical tracking has been shown to correct slice misalignment and non-linear spin-history artifacts, however residual artifacts due to dynamic magnetic field non-uniformity may remain in the data. A recently developed correction technique, PLACE, can correct for absolute geometric distortion using the complex image data from two EPI images, with slightly shifted k-space trajectories. We present a correction approach that integrates PLACE into a real-time scan-plane update system by optical tracking, applied to a tissue-equivalent phantom undergoing complex motion and an fMRI finger tapping experiment with overt head motion to induce dynamic field non-uniformity. Experiments suggest that including volume by volume geometric distortion correction by PLACE can suppress dynamic geometric distortion artifacts in a phantom and in vivo and provide more robust activation maps.

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.

No / Recreational use of 3,4-methylenedioxymethamphetamine (MDMA; "ecstasy") poses worldwide potential health problems. Clinical studies show that repeated exposure to low oral doses of MDMA has toxic effects on the brain, altering cognitive and psychosocial behavior. Functional magnetic resonance imaging in conscious marmoset monkeys was used to evaluate the sensitivity of the brain to an oral dose of MDMA (1 mg/kg). Following MDMA administration, the midbrain raphe nuclei and substantia nigra, major sources of serotonin and dopamine, were activated as were the hippocampus, hypothalamus and amygdala. The corticostriatal circuit of dorsal thalamus, sensorimotor cortex and basal ganglia showed a robust, coherent activation pattern. Two key reward areas, the nucleus accumbens and prefrontal cortex, and most other cortical regions showed little activation. The visual cortex, however, showed intense activation without applied visual stimuli. These data identify brain areas and functional circuits sensitive to a recreational dose of MDMA, some of which may be vulnerable to long-term intermittent exposure to this drug.

none

Examination of functional brain anatomy is a crucial step in the process of surgical removal of many brain tumors. Functional magnetic resonance imaging (fMRI) is a promising technology capable of mapping brain function non-invasively. To be successfully applied to presurgical mapping, there are questions of diagnostic accuracy that remain to be addressed. One of the greatest difficulties in implementing fMRI is the need to define an activation threshold for producing functional maps. There is as of yet no consensus on the best approach to this problem, and a priori statistical approaches are generally considered insufficient because they are not specific to individual patient data. Additionally, low signal to noise and sensitivity to magnetic susceptibility effects combine to make the production of activation maps technically demanding. This contributes to a wide range of estimates of reproducibility and validity for fMRI, as the results are sensitive to changes in acquisition and processing strategies. Test-retest fMRI imaging at the individual level, and receiver operator characteristic (ROC) analysis of the results can address both of these concerns simultaneously. In this work, it is shown that the area under the ROC curve (AUC) can be used as an indicator of reproducibility, and that this is dependent on the image thresholds used. Production of AUC profiles can thus be used to optimize the selection of individual thresholds on the basis of detecting stable activation patterns, rather than a priori significance levels. The ROC analysis framework developed provides a powerful tool for simultaneous control of protocol reproducibility and data driven threshold selection, at the individual level. This tool can be used to guide optimal acquisition and processing strategies, and as part of a quality assurance program for implementing presurgical fMRI.

<p>An inescapable component to survival in a dynamic environment is detecting and reacting to signals of danger. One of the most elegant processes animals possess to handle this complex task is classical conditioning, wherein stimuli associated with an aversive event acquire the capacity to elicit defensive behaviors. This process helps ensure quick reactions prior to the occurrence of an imminent threat. A problem of living in a dynamic environment, however, is that reliable signals of danger are rarely re-encountered in the exact same form from one situation to the next. Thus, to be truly adaptive it is imperative for defensive responses to extend beyond a specific instance towards other exemplars that might portend the same negative outcome. While the phenomenon of stimulus generalization was recognized in the earliest studies of conditioning from Pavlov's laboratory, a century of conditioning research has not resolved how humans and other animals actually meet this challenge. The research presented herein employs a combination of psychophysiological and functional imaging methods to examine how humans recruit neurocognitive systems to determine what stimuli do (and do not) pose a threat. Results show that human fear generalization is a complex phenomenon affected by the perceptual and conceptual nature of the stimulus. Brain regions and functional networks involved in fear generalization comprise cortical areas involved in coding the representation of conditioned stimuli and subcortical regions involved conditioned learning and the production of behavioral responses, most notably the amygdala. These results reveal the importance of stimulus-specific factors in fear learning and generalization, provide support for anatomically constrained models of fear generalization, and contribute to the development of model systems of fear generalization processes in human anxiety disorders.</p> / Dissertation