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Full-Text Articles in Medicine and Health Sciences
Role Of The Default-Mode Network During Narrative Integration In Major Depressive Disorder, Darren Ri-Sheng Liang
Role Of The Default-Mode Network During Narrative Integration In Major Depressive Disorder, Darren Ri-Sheng Liang
Electronic Thesis and Dissertation Repository
How brain activity is synchronized across individuals during narrative comprehension has previously been characterized by functional magnetic resonance imaging (fMRI) in healthy and patient populations. To our knowledge, there has been limited investigation as to how it is affected by major depressive disorder (MDD). We addressed this issue with fMRI through examination of inter-subject synchronization in the default mode network (DMN), brain structures which have previously been implicated in MDD pathology. Twenty-two patients with MDD and 20 matched control participants listened to Intact versus Scrambled versions of an auditory narrative; these experimental conditions differed in the degree of temporal integration …
Inter-Subject Correlation Using Movie-Driven Fmri In Drug-Resistant Epilepsy, Hana H. Abbas
Inter-Subject Correlation Using Movie-Driven Fmri In Drug-Resistant Epilepsy, Hana H. Abbas
Electronic Thesis and Dissertation Repository
Treating drug-resistant epilepsy with surgery requires the localization of the epileptic focus. We explored the potential for movie-driven functional magnetic resonance imaging (fMRI) to act as a sensitive, non-invasive, and cost-effective tool to identify functionally disturbed networks. We assessed neural synchronization (inter-subject correlation; ISC) between presurgical epilepsy patients (n = 18) and healthy controls (n = 24) as they watched a suspenseful movie clip in the scanner. To optimize denoising, we compared ISC values with and without an automated Independent Components Analysis-based denoising step (ICA-AROMA). We found that denoising with ICA-AROMA elicited augmented correlation values, supporting its use …
Evaluating Anesthetic Protocols For Non-Human Primate Functional Neuroimaging, Megha Verma
Evaluating Anesthetic Protocols For Non-Human Primate Functional Neuroimaging, Megha Verma
Electronic Thesis and Dissertation Repository
Functional magnetic resonance imaging (fMRI) is a non-invasive technique that can be used to measure a proxy of neural activity in vivo with high spatial specificity. One subject can be followed for a long period of time to assess changes in functional brain organization. However, fMRI is extremely sensitive to motion. The challenges of training non-human primates to reduce motion in an MRI scanner motivate the study of anesthesia which is commonly used to substitute for this training. In this thesis, I compare three different commonly used anesthetic protocols: isoflurane, propofol-fentanyl in combination, and fentanyl alone, to test which of …
Optimizing Preprocessing Of Fmri Data To Maximize Correspondence Of Functional Anatomy Across Individuals, Nargess Ghazaleh
Optimizing Preprocessing Of Fmri Data To Maximize Correspondence Of Functional Anatomy Across Individuals, Nargess Ghazaleh
Electronic Thesis and Dissertation Repository
In movie-activation fMRI, intersubject correlation (ISC) indicates a functional correspondence across viewers. Brains di↵er in shape; spatial normalization and smoothing enhance inter-subject functional overlap. We compare three normalization methods and six smoothing levels to discover which method yields the best functional overlap, indexed by ISC. This is key to optimizing data analysis in clinical studies using movie-activation fMRI in future. In a 3T scanner, 44 healthy subjects watched an 8-min movie. Both normalization and smoothing a↵ected the strength and extent of the ISC. ISC values were more robust for ANTs and DARTELthanforSPM12andwere(asymptotically)thestrongestat12mmsmoothing. When image data are preprocessed with high-dimensional volumetric …
Covert Narrative Capacity: Mental Life In Patients Thought To Lack Consciousness, Lorina Naci, Mackenzie Graham, Adrian M. Owen, Charles Weijer
Covert Narrative Capacity: Mental Life In Patients Thought To Lack Consciousness, Lorina Naci, Mackenzie Graham, Adrian M. Owen, Charles Weijer
Anatomy and Cell Biology Publications
Despite the apparent absence of external signs of consciousness, a significant proportion of behaviorally nonresponsive patients can respond to commands by willfully modulating their brain activity. However, little is known about the mental life of these patients. We discuss a recent innovative approach, which sheds light on the preserved cognitive capacities of these patients, including executive function, theory of mind, and the experience of affective states. This research represents a fundamental shift in our understanding of these patients, and has important implications for both their continued treatment and care. Moreover, this research marks out avenues for future inquiry into the …
Decoding Motor Intentions From Human Brain Activity, Jason P. Gallivan
Decoding Motor Intentions From Human Brain Activity, Jason P. Gallivan
Electronic Thesis and Dissertation Repository
“You read my mind.” Although this simple everyday expression implies ‘knowledge or understanding’ of another’s thinking, true ‘mind-reading’ capabilities implicitly seem constrained to the domains of Hollywood and science-fiction. In the field of sensorimotor neuroscience, however, significant progress in this area has come from mapping characteristic changes in brain activity that occur prior to an action being initiated. For instance, invasive neural recordings in non-human primates have significantly increased our understanding of how highly cognitive and abstract processes like intentions and decisions are represented in the brain by showing that it is possible to decode or ‘predict’ upcoming sensorimotor …