The reach-to-eat movement, in which a hand is advanced towards a food item, shapes to grasp the food item, and withdrawals to place the food item into the mouth for eating, is a behaviour that is performed daily. The movement is controlled by two sensory systems, vision to guide hand advance and grasping, and somatosensation to guide hand withdrawal and mouth placement. The purpose of the present thesis was to examine how the sensory control of reaching-to-eat develops in infancy and degenerates following neurodegenerative disorder. The tight coupling of vision to hand advance and somatosensation to hand withdrawal has a developmental profile from six months to one year of age. That is, six-month-old infants rely on vision to advance their hand, grasp the target, and withdrawal the target to the mouth. By twelve months of age, infants display the adult pattern of coupling vision to hand advance and grasping. The tight coupling of vision to hand advance degenerates with basal ganglia disease, such that subjects with Parkinson’s disease and Huntington’s disease show an overreliance on vision to guide hand advance for grasping and hand withdrawal for mouth placement. The results of the thesis demonstrate that efficient use of sensory control to guide motor behaviour is an important aspect of development that is disrupted by neurodegenerative disease. / xiv, 286 leaves : ill. ; 29 cm

The development of Parkinson's disease (PD) in humans has been linked to genetic and environmental factors for many years. However, finding common single insults which can produce pathology in humans has proved difficult. Exposure to trichloroethylene (TCE) or traumatic brain injury (TBI) has been shown to be linked to PD and it has also been proposed that multiple insults may be needed for disease development. The present studies show that exposure to TCE prior to a TBI can result in pathology similar to early PD and that the interaction of both insults is required for impairment in behavioral function, and cell loss. Following exposure to TCE for 2 weeks there is a 75% impairment in mitochondrial function but it has yet to be shown if the addition of a TBI can make this worse. If the exposure to TCE is reduced to 1 week and combined with TBI a 50% reduction in mitochondrial function is observed following the dual injury which requires both insults. These studies provide further support for the hypothesis that PD may result from a multifactorial mechanism. It had been established that regional differences exist in mitochondrial function across brain regions. The present studies indicate that previous findings are not likely to be the result of differences in individual mitochondria isolated from the cortex, striatum, and hippocampus. Further analysis of the effect of mitochondrial inhibitors on enzyme activity and oxygen consumption reveal that the different regions of the brain are similarly affected by the inhibitors. These results suggest that findings from previous studies indicating regionally specific deficits following systemic toxin exposure, such as with TCE, are not the result of regional differences in the individual mitochondria. Given that TBI results in significant dysfunction, finding effective therapeutics for TBI will provide substantial benefits to individuals suffering an insult. Treatment with Pioglitazone following TBI reduced mitochondrial dysfunction, cognitive impairment, cortical tissue loss, and inflammation. These findings provide initial evidence that treatment with Pioglitazone may be an effective intervention for TBI.

Tal- och röstförändringar är vanligt förekommande hos personer med Parkinsons sjukdom. Dessa påverkar ofta talarens förståelighet men kan också ha en negativ inverkan på talets naturlighet. Forskning angående vilka faktorer som påverkar talets naturlighet är i dagsläget begränsad, varför föreliggande studie har genomförts. Syftet med studien var att undersöka huruvida den uppfattade talnaturligheten kunde härledas till några specifika tal- och röstparametrar. I föreliggande studie konstruerades ett testbatteri för att elicitera talmaterial från åtta personer med Parkinsons sjukdom. Forskningspersonernas röster spelades in och inspelningarna graderades sedan av 27 naiva lyssnare gällande förståelighet och talnaturlighet. Korrelationstester genomfördes slutligen för att hitta eventuella samband mellan lyssnarnas bedömning och olika akustiska parametrar. Resultatet visade att tal- och artikulationshastighet var den faktor med störst inverkan på lyssnargruppens bedömning av talnaturlighet, där de med långsammast hastighet bedömdes ha mest onaturligt tal. Vidare fanns starka indikationer på att grad av förståelighet korrelerade med bedömningen av talnaturlighet. I föreliggande studie tycktes inga övriga akustiska parametrar ha en statistiskt signifikant korrelation med lyssnargruppens bedömning av talnaturlighet. / Speech and voice changes are common in Parkinson’s disease. These changes can affect the speaker’s intelligibility but can also have a negative impact on the perceived naturalness of speech. The research available regarding the different factors that affect speech naturalness is scarce, which was the motivation behind this study. The aim of the present study was to investigate whether the level of perceived speech naturalness could derive from any specific aspects of speech. This was accomplished by recording speech samples from eight people with Parkinson’s disease using a test battery with various speech tasks. These samples were presented to a group of 27 naive listeners whose task was to judge the level of intelligibility as well as the level of speech naturalness. Correlations were then made between their assessments and various acoustic measurements. The main finding of the present study was that speech and articulation rate seemed to have the greatest impact on the perceived level of naturalness, where the people who had the slowest rate were judged to be the least natural sounding. Furthermore there were strong indications that the level of intelligibility correlated with the level of speech naturalness. In this study there were no other acoustic correlates found with statistical significance.

Alpha-synuclein (AS) is a natively unfolded protein whose structure is extremely sensitive to its environment. The hallmark of Parkinson’s disease (PD) is aggregation and deposition of AS in inclusion bodies. Formation of misfolded AS monomers which are partially folded is the first and critical stage in fibrillation of AS and is a good target for designing therapeutic strategies. Characterization the biochemical properties of partially folded intermediates induced by fibrillization and anti- fibrillization agents will help to design drugs as new inhibitors of AS misfolding and aggregation. Nanopore analysis is an emerging technique for studying the molecular mechanism of protein misfolding. This technique was used to characterize the conformational change of AS in the presence of two groups of chemicals; anti-parkinsonian small molecules (dopamine and nicotine) and Parkinson’s developing toxin (Cu(II) and methamphetamine). Other biophysical techniques such as NMR spectroscopy and isothermal titration calorimentry (ITC) were able to confirm the nanopore analysis results and also to study other biophysical properties of the partially folded intermediates such as the binding constant of the interaction and the secondary structure content. The results from nanopore analysis showed that both groups of ligands shifted the blockade current peak of AS (centered at -86 pA) to lower blockade currents but in a different manner. Anti-parkinsonian drugs shifted the blockade current of AS to intermediate peaks between -40 to -80 pA but Parkinson developing toxins shifted the peak to a lower blockade current centered at -25 pA which suggests a more compact conformation. Thus nanopore analysis distinguished the different conformation induced by different ligands. Furthermore nanopore analysis with AS fragments showed that these ligands bind to different regions of AS. NMR spectroscopy of AS in the presence of dopamine and nicotine isomers was in agreement with the nanopore analysis and showed conformational changes of AS in a concentration dependent manner. CD spectroscopy results showed that the secondary structure of AS alone and in the presence of ligands was mostly random coil and suggests a loop formation model for the interaction of ligands with AS. The results of this thesis showed the application of nanopore analysis as a real-time and label-free technique to screen a library of ligands for designing misfolding inhibitors for PD treatment. The result of a synergic experiment with nicotine and caffeine showed that combination of these anti-parkinsonian small molecules would be a promising new drug for treatment of PD.

No description available.

Parkinson’s disease (PD) is a common neurodegenerative disorder that is characterized by the degeneration of dopaminergic (DA) neurons in the substantia nigra and motor deficits. Although the majority of PD cases are sporadic, several genetic defects in rare familial cases have been identified. Animal models of these genetic defects have been created and have provided unique insights into the molecular mechanisms of the pathogenesis of PD. However, the etiology of PD is still not well understood. Here, taking advantage of the unique features offered by zebrafish, I characterized the functions of PINK1 (PTEN-induced kinase 1) gene, which is associated with recessive familial PD, in the development and survival of DA neurons. In zebrafish, antisense morpholino knockdown of pink1 did not cause a large loss of DA neurons in the ventral diencephalon (vDC), but the patterning of these neurons and their projections were perturbed. The pink1 morphants also showed impaired response to touch stimuli and reduced swimming behaviour. Moreover, the pink1 knockdown caused a significant reduction in the number of mitochondria, as well as mitochondrial morphological defects such as smaller size or loss of cristae, thus affecting mitochondrial function. These results suggest that zebrafish pink1 plays conserved important roles in the development of DA neurons and in the mitochondrial morphology and function. To better follow DA neurons after injury or administration of toxins, I generated a transgenic zebrafish line, Tg(dat:EGFP), in which the green fluorescent protein (GFP) is expressed under the control of cis-regulatory elements of dopamine transporter (dat). In Tg(dat:EGFP) fish, all major groups of DA neurons are correctly labeled with GFP, especially the ones in the vDC, which are analogous to the ascending midbrain DA neurons in mammals. In addition, we observed that the DA neurons in the vDC could partially be replaced after severe laser cell ablation. This suggests that zebrafish may have the unique capacity of regenerating DA neurons after injury. Taken together, my studies suggested that zebrafish could be a useful alternative animal model for the study of the molecular mechanisms underlying PD and for the screening of potential therapeutic compounds for PD.

Microglia activity has been detected in Parkinson’s disease (PD) post-mortem brains and experimental animal models; however the precise interplay between microglia and dopamine neurons of the SNpc is not well understood. In the blood plasma of PD patients, our laboratory found elevated levels of interferon-gamma (IFN-γ), a proinflammatory cytokine and potent activator of microglia. Given this, we sought to untangle the immune responses relevant to PD in mice, examining IFN-γ’s involvement and signaling mechanism using an inflammatory co-culture model of microglia and midbrain neurons treated with rotenone. By means of RT-PCR, we discovered IFN-γ mRNA transcripts are produced by microglia, and this expression increases upon exposure to rotenone. We delineated IFN-γ’s signaling mechanism in co-cultures using different IFN-γ receptor deficient cells, and showed it engages receptors in an autocrine (not paracrine) manner to further microgliosis and dopamine cell loss. After exploring the innate immune response in a model of PD, we subsequently shifted focus to an in vivo system to better investigate any involvement of the delayed humoral arm of the adaptive immune system. Needing a time appropriate death paradigm, we developed a protracted low dose regimen of MPTP, which elicits dopaminergic cell death after 2 weeks of treatment. Subjected to this paradigm, Rag 2 mutant mice (deficient in both T and B cells) exhibit resistance to dopamine cell loss, microglia activation and motor impairments. Further evidence in support of immune involvement came with the resensitization of Rag2 mice to MPTP after reconstitution with WT splenocytes. Additionally, mice deficient in Fcγ receptors exhibited neuroprotection in our protracted degeneration model. Taken together, these data indicate the innate and humoral arm can modulate the microglial response to dopaminergic degeneration and may participate in Parkinson's disease.

Parkinson’s disease is a neurodegenerative disease resulting primarily from loss of dopaminergic innervation in the striatum subsequent to cell loss in the substantia nigra pars compacta. The abnormal accumulation of the normal pre-synaptic protein α-synuclein (αsyn) forms intraneuronal inclusions known as Lewy neurites and Lewy bodies. The origins of central Lewy pathology have been suggested to lie in the enteric nervous system, ascending through the vagus nerve to the dorsal motor nucleus of the vagus. To ascertain gastrointestinal regions most likely to be the source of central Lewy pathology, αsyn expression was evaluated in the neural elements of gastrointestinal regions receiving the densest vagal innervation. The vermiform appendix was found to have the densest αsyn-immunoreactive innervation in all layers of the gut wall. In addition, macrophages in the appendiceal mucosa were laden with αsyn within lysosomes, consistent with attempts to prevent the spread of disease or to correct synaptic dysfunction.

The aim of this thesis was the functional characterization of the zebrafish parl (Presenilin-Associated Rhomboid-Like) genes which code for mitochondrial proteins involved in cell survival. A mutation in PARL has been described in Parkinson’s disease patients. I investigated the role of mitochondrial PD-related proteins using a zebrafish parla and parlb deficiency model. I found that the knockdown of both parl genes is lethal. Parla plays a larger role in patterning of the DA neurons in the ventral diencephalon than Parlb. The human PARL rescued the double morphant phenotype, suggesting function conservation between zebrafish and humans. I was able to rescue the mortality and DA neuron mispatterning observed in double morphants with synthetic pink1 mRNA. This suggests that parl genes are epistatic to pink1 in zebrafish. To visualize mitochondria specifically in dopaminergic neurons of live zebrafish, I established a transgenic line Tg(dat:tom20 MLS-mCherry) where regulatory elements of the dopamine transporter (dat) were used to drive expression of a Tom20-mCherry fusion protein that is targeted to the mitochondria. I characterised the expression of Tom20-mCherry to the mitochondria of the majority of DA neuron groups. In addition, I observed a decrease in mCherry fluorescence following MPTP exposure of live fish. The PD-related mutation in PARL is located in a cleavage site of the mammalian protein, which is necessary for the production of the beta peptide; however, this site is predicted to be absent in the zebrafish Parls. To establish the cleavage patterns of the zebrafish Parls and compare them to those of human PARL, I examined the cleavage of Parl-Flag constructs in cultured cells. I detected one band for Parla-Flag and two bands representing Parlb-Flag. The parla and parlb deficiency model along with the characterization of the cleavage patterns of Parl and the Tg(dat:tom20 MLS-mCherry) transgenic line are tools which will help elucidate the role of mitochondrial proteins in PD research.

I will investigate applications of machine learning algorithms to medical data, adaptations of differences in data collection, and the use of ensemble techniques. Focusing on the binary classification problem of Parkinson’s Disease (PD) diagnosis, I will apply machine learning algorithms to a primary dataset consisting of voice recordings from healthy and PD subjects. Specifically, I will use Artificial Neural Networks, Support Vector Machines, and an Ensemble Learning algorithm to reproduce results from [MS12] and [GM09]. Next, I will adapt a secondary regression dataset of PD recordings and combine it with the primary binary classification dataset, testing various techniques to consolidate the data including treating the regression data as unlabeled data in a semi-supervised learning approach. I will determine the performance of the above algorithms on this consolidated dataset. Performance of algorithms will be evaluated using 10-fold cross validation and results will be analyzed in a confusion matrix. Accuracy, precision, recall, and F-score will be calculated. The expands on past related work, which has used either a regression dataset alone to predict a Unified Parkinson’s Disease Rating Scale score for PD patients, or a classification dataset to determine healthy or PD diagnosis. In past work, the datasets have not been combined, and the regression set has not been used to contribute to evaluation of healthy subjects.