Neuroscience and Neurobiology Commons^™

Mapping The Functional Organization Of Human Frontoparietal Cortex With Fmri, Geetika Gupta

Electronic Thesis and Dissertation Repository

Higher-order cognitive functions, such as working memory, attention, and decision making, depend strongly on the functional integrity of frontal and parietal cortices. However, the internal workings of the frontoparietal network (FPN) are not well understood. A major contributor to this knowledge gap is our limited understanding of the intrinsic functional organization of the FPN. In order to address this gap, we examine task-dependent reconfigurations of functional connectivity (FC) within the FPN. We analyzed fMRI task-state data from 924 individuals from the Human Connectome Project Young Adult study. Our results show that FC within the FPN is highly stable across time …

Resting State Network Dynamics Across Wakefulness And Sleep, Evan Houldin

Electronic Thesis and Dissertation Repository

The function of sleep is a longstanding mystery of the brain. By contrast, the function of resting state networks (RSNs) is one of its most recent mysteries. The relationship between RSNs and neuronal activity has been unclear since RSNs were discovered during the advent of functional magnetic resonance imaging (fMRI). Somewhat paradoxically, investigating these enigmatic phenomena in parallel can help to illuminate the function of both. The three studies described as part of this thesis all involve an evaluation of RSN dynamics across wakefulness and sleep. They are all based on the same dataset, derived from an experimental paradigm in …

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, …

Movie-Driven Fmri Reveals Network Asynchrony And Connectivity Alterations In Temporal Lobe Epilepsy, Alenka Bullen

Electronic Thesis and Dissertation Repository

Mesial temporal lobe epilepsy (TLE) is the most common form of focal epilepsy and is often resistant to medication. Recent studies have noted brain-wide disruptions to several neural networks in so-called “focal” epilepsy, notably TLE, leading to it being recognized as a network disease. We aimed to assess the integrity of functional networks while they were simultaneously activated in an ecologically valid manner, using an actively engaging, richly stimulating audio-visual film clip. This stimulus elicits widespread, dynamic patterns of time-locked brain activity, measurable using functional magnetic resonance imaging. Thirteen persons with drug-resistant TLE (persons with epilepsy; PWE) and 10 demographically …

Functional Connectivity In The Motor Network Largely Matures Before Motor Function, Jordynne L V Ropat

Electronic Thesis and Dissertation Repository

The brain changes in many ways in the first year. It is not known which of these changes are most critical for the development of cognitive functions. According to the Interactive Specialization Theory, developments in behaviour result from changes in brain connectivity. We tested this using functional connectivity magnetic resonance imaging (fcMRI) of the motor system. fcMRI was acquired at three and nine months – two time-points between which motor behaviour develops enormously. Infants were additionally compared with adults. Subjects were scanned with a 3T MRI scanner, yielding BOLD signal time-courses that were correlated with one another. Our results do …

Toward A Functional Characterization Of Cognitive Control Networks, Frederick Ezekiel

Electronic Thesis and Dissertation Repository

Cognitive control is an executive process that has been associated with a distributed set of cortical regions. These distributed regions appear to cluster into distinct networks with dissociable functions. In this study, independent component analysis was used as a tool to investigate functional connectivity in event-related fMRI data. Extracted networks of interest were functionally characterized using a hybrid task that independently probed moment-to-moment adjustments in control, and stable task-set maintenance. A cinguloinsular network was implicated in the processing of moment-to-moment adjustments in control based on its activation patterns during this task. Subsequently, functional connectivity between two networks previously implicated in …