Systems Neuroscience Commons^™

Individual Differences In Age And Testosterone Are Uniquely Associated With Neural Oscillatory Activity Serving Verbal Working Memory In Children And Adolescents, Abraham D. Killanin

Theses & Dissertations

During the sensitive period of adolescence, the human brain undergoes dynamic changes in structure and function resulting in vast executive function gains. Verbal working memory (VWM) is one executive function that serves as a foundation to language acquisition, reading, and learning. Many have examined the development of VWM in youth, but few have probed age-related changes in the underlying neural oscillatory dynamics, and none have examined testosterone-related changes. We recorded magnetoencephalography during a modified Sternberg VWM task in 82 youth participants aged 6 – 14 years old and collected salivary testosterone samples. Significant oscillatory responses were identified and imaged using …

The Effect Of Repetitive Transcranial Magnetic Stimulation On Brain And Cognitive Variables In Patients With Amnestic Mild Cognitive Impairment, Connor J. Phipps

Theses & Dissertations

Healthy and pathological aging processes can impact human memory. Current interventions for clinical memory impairment offer little opportunity for restoration of memory ability. Fortunately, a novel therapy in the form of repetitive transcranial magnetic stimulation (rTMS) has exhibited promise in this regard. In healthy adults, rTMS of the angular gyrus (AG) has been reported to improve memory. The current study sought to determine the generalizability of these findings to individuals with clinical memory impairment by administering a clinical trial replicating an rTMS protocol reported to improve hippocampal-dependent memory in healthy individuals to individuals with amnestic mild cognitive impairment (aMCI). Individuals …

Aberrant Age-Related Alterations In Spontaneous Cortical Activity In Participants With Cerebral Palsy, Hannah Bergwell

Theses & Dissertations

Cerebral Palsy (CP) is the most common neurodevelopmental motor disability, resulting in life-long sensory, perception and motor impairments. These impairments appear to drastically worsen with advancing age within the CP population, although the underlying neuro-physiological mechanisms remain poorly understood. Herein, we began to address this knowledge gap by utilizing magnetoencephalographic (MEG) to study how aging impacts the amplitude of spontaneous brain activity (i.e., resting state) in a cohort of 38 individuals with spastic diplegic CP (Age = 22.08 ± 10.46 years) and 67 neurotypical controls (NT) (Age = 19.56 ± 10.25 years). Participants completed an eyes-closed resting-state paradigm while undergoing …

Linking Spinal Cord Circuits With Upper Limb Sensorimotor Control In Adults With Cerebral Palsy, Saihari Dukkipati

Theses & Dissertations

Cerebral palsy (CP) is the most common neurological disorder originating in childhood, but most of the people living with CP are currently adults. While people with CP continue to get older, the amount of research focused on adults has been rather limited. The early childhood insults leading to CP are thought to originate in the brain, but the effects on the entire neuromuscular system across the lifespan have only recently started to be explored. Of note, recent neuroimaging evidence suggests that the cervical spinal cord structure is atypical in adults with CP. However, it is largely unclear how the neurophysiological …

The Neurological Abnormalities Of The Brain And Spinal Cord In Individuals With Cerebral Palsy, Michael Trevarrow

Theses & Dissertations

Cerebral palsy (CP) results from an insult to the developing brain, and it is one of the most common neurodevelopmental disorders in the United States. The insult produces a cascade of activity-dependent plastic changes within the neurophysiology and structure of the brain and spinal cord that ultimately leads to sensorimotor and mobility impairments that may increase in severity throughout the lifespan. Despite this phenomenon, there are a lack of neuroimaging studies in adults with CP, generating a knowledge gap in determining how brain and spinal cord activity and structure may be altered throughout the transition into adulthood. Furthermore, the specific …

Multimodal Neuroimaging Of Hiv And Aging, Brandon Lew

Theses & Dissertations

HIV infection remains a significant contributor to disease burden, and with the success of antiretroviral therapies, the population of people with HIV is aging. A growing literature suggests a relationship between HIV-infection and a profile of age advancement, most notably in molecular studies of epigenetics. However, despite the widely-known high prevalence of HIV-related brain atrophy, functional deficits, and HIV-associated neurocognitive disorder (HAND), epigenetic age advancement has not been linked to HIV-related changes in neuroimaging metrics.

We applied three neuroimaging methods, structural MRI, resting state functional MRI, and resting state MEG, to study the brain structure and function of 121 virally-suppressed …

The Neurophysiological Changes Associated With Motor Learning In Adults And Adolescents, James E. Gehringer

Theses & Dissertations

One main purpose of this dissertation was to explore how sensorimotor cortical oscillations changed after practicing a novel ankle plantarflexion target matching task. We behaviorally quantified the speed, accuracy, reaction time, velocity, and variability of the participant’s performance of the task, while collecting their neurophysiological responses with magnetoencephalography (MEG). With these data, we assessed how the motor planning and execution stages of movement during a goal directed target matching task changed after practicing a task in typically developing young adults with their non-dominant ankle. We found that the cortical oscillations in the beta frequency range that were sourced from the …

Motor Control In Individuals With Multiple Sclerosis, David Arpin

Theses & Dissertations

This dissertation explored motor control in individuals with multiple sclerosis (MS) by quantifying the behavioral and neurophysiological deficits present in these individuals. We behaviorally quantified the precision of the ankle plantarflexor musculature of individuals with MS. Our results indicated that the individuals with MS had a greater amount of variability in the precision of the isometric ankle torques, and that this greater variability was related to decreased walking performance. To further explore whether these motor control deficits were due to aberrant cortical activity associated with planning motor actions, we used magnetoencephalography to assess the motor planning and execution stages of …

Global Gene Expression Profiling Of Healthy Human Brain And Its Application In Studying Neurological Disorders, Simarjeet K. Negi

Theses & Dissertations

The human brain is the most complex structure known to mankind and one of the greatest challenges in modern biology is to understand how it is built and organized. The power of the brain arises from its variety of cells and structures, and ultimately where and when different genes are switched on and off throughout the brain tissue. In other words, brain function depends on the precise regulation of gene expression in its sub-anatomical structures. But, our understanding of the complexity and dynamics of the transcriptome of the human brain is still incomplete. To fill in the need, we designed …