Medicine and Health Sciences Commons^™

Serotonergic System And Gait: Dorsal Raphe Nucleus As A Control System For Gait, Nahal Farhani

Electronic Thesis and Dissertation Repository

In advanced stages of Parkinson Disease (PD), gait and postural abnormalities emerge. These symptoms are not prominent at early stages of PD despite significant dopaminergic neuronal loss. Gait abnormalities are largely not responsive to levodopa. Therefore, other types of neurons might be responsible for gait abnormalities of the PD.

Since the reticulospinal tract (RET) is mainly implicated in the control of axial muscles, the degeneration of this pathway or populations of neurons controlling this pathway might be responsible for axial symptoms. However, there is limited data about the neurons controlling the RET. Our aim in this study is to delineate …

Deep Brain Stimulation And Its Effects On Parkinson Disease Spatiotemporal Gait Parameters., Greydon Gilmore

Electronic Thesis and Dissertation Repository

Subthalamic (STN) deep brain stimulation (DBS) alleviates common appendicular PD symptoms, such as: tremor, rigidity and bradykinesia. However, the effect STN-DBS has on modulating axial gait features has not been properly quantified objectively. The purpose of the present thesis was to investigate the role STN-DBS plays in modulating specific gait features such as pace, asymmetry, variability, rhythm and postural control. It is hypothesized that axial gait function is regulated predominantly by non-dopaminergic control systems. In the acute immediate post-operative phase a surgical effect, named the microlesion effect (MLE), is thought to produce a transient improvement of appendicular and axial symptoms. …

Quantifying The Effects Of Systematic Stn-Dbs Programming On Rest And Postural Tremor In Idiopathic Parkinson Disease Patients, Kristina Ognjanovic

Electronic Thesis and Dissertation Repository

Parkinson’s disease (PD) is a complex neurodegenerative disorder that encompasses both motor and non-motor symptoms. These symptoms and their severity are typically assessed by scale based measures in a clinical setting. Scale- based assessments of PD patients undergoing bilateral subthalamic nucleus deep brain stimulation surgery (STN-DBS) such as the Unified Parkinson Disease Rating Scale (UPDRS) are commonly used in a clinical setting to assess symptom severity and progression. However, the subjective nature of these and other clinical scales call into question both the sensitivity and accuracy of patient assessment over time. An objective quantification of rest and postural tremor of …

Contribution Of The Dorsolateral Prefrontal Cortex To Attentional And Mnemonic Processes In Visual Search, Brandon Belbeck

Electronic Thesis and Dissertation Repository

A key characteristic of selective visual attention is that it may be deployed on the basis of our knowledge or goals of the task at hand. Here, we used cryogenic deactivation to investigate the contribution of the dorsolateral PFC to cognitive flexibility and working memory, as well as their relation to the deployment of attention. Macaque monkeys performed visual search tasks requiring them to foveate a target in an array of stimuli. These included a feature search, a constant-target conjunction search, a variable-target search and variable-target with delay search task, with each being more cognitively demanding than the last. Bilateral …

Resting-State Functional Network Disruptions In A Rodent Model Of Mesial Temporal Lobe Epilepsy (Tle), Ravnoor Singh Gill

Electronic Thesis and Dissertation Repository

Mesial temporal lobe epilepsy (TLE) is the most common form of drug-refractory epilepsy. The clinical application of non-invasively mapped networks using resting-state functional magnetic resonance imaging (rsfMRI) in humans has been rather limited due to heterogeneous (varying etiology, drugs, onset, latent period, etc.) patient groups. We employed a pharmacological (kainic acid) rodent model of TLE to measure the extent of functional network disruptions using rsfMRI, and study selected behaviors and olfactory to hippocampus transmission. Graph theoretical network modelling and analysis revealed significant increase in functional connectivity connectivity to the temporal lobe (hippocampus) in epileptic-rats compared to controls in the limbic …