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Functional connectivity and brain structure assessment in patients at risk of synucleinopathies
Klobušiaková, Patrícia ; Gajdoš, Martin (oponent) ; Mekyska, Jiří (vedoucí práce)
Synucleinopathy is a neurodegenerative disorder characterized by the presence of pathological protein -synuclein in neurons. So far, treatment that could heal or permanently stop this disease is not known. The aim of this work is to identify prodromal stages of synucleinopathies using functional connectivity processed applying graph metrics and assessing cortical thickness and subcortical structures volumes from magnetic resonance imaging data, and to verify specificity and sensitivity of combinations of parameters that sufficiently differentiate patients in risk of synucleinopathies. To accomplish this goal, we collected data from patients in the risk of synucleinopathy (preDLB, n = 27) and healthy controls (HC, n = 28). We found reduced volume of right pallidum and increased hippocampal volume to cortical volume ratio, increased normalised clustering coefficient and higher modularity in the preDLB group in comparison to HC. These four parameters were modeled using machine learning. The resulting model differentiated preDLB and HC with balanced accuracy of 88 %, specificity of 89 % and sensitivity of 86 %. The findings of this thesis can serve as the basis for further studies searching for specific MRI markers of prodromal stage of synucleinopathy that could be targeted with therapy in the future.
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Calculating the Cortical Thickness of Brain by using electrical and mathematical models for Optimal Transcranial Direct Current Stimulation
Hamza, Ali ; Mezl, Martin ; Zafar, Saima
transcranial direct current stimulation (tDCS) is one of the most well-known brain stimulation techniques. In this technique, a constant low intensity (4mA to 5mA) current provides to the brain to modulate the excitability of neurons. There are two categories of tDCS, and both are used for diagnosing different neural disorders, one is anodal stimulation and the other one is cathodal stimulation. Anodal stimulation is used for patients of stroke, epilepsy and depression. Whereas cathodal stimulation is helpful for the obesity, drug addiction and hypertension. The aim of this research was to improve the efficiency of tDCS which depends on the intensity and magnitude of current applied for stimulation. It is important to note that there are numerous variables that can alter the intensity of the current. Some of these variables are hair thickness, head size, skull, tissues thickness, cortical fluid thickness, age, cortical thickness of the brain. In this article, the cortical thickness of the brain is estimated, and the current intensity is calculated for a patient. The Magnetic resonance images (MRI) data of 8 male subjects are analyzed, the raw MRIs are preprocessed, and layers of the head are segmented using MATLAB tool statistical parametric mapping (SPM). After the segmentation of these layers, we calculated the combined thickness of these layers to calculate the desired value of current. The authenticity of our results is compared with the standard current values. Our results shows that the calculated current intensity is closely matched with the standard values and is a direct function of the cortical thickness of brain which is computed from the MRIs. We claim that using our computation, the stimulation current is more accurate and is patient dependent instead of applying the same current to every patient.
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Functional connectivity and brain structure assessment in patients at risk of synucleinopathies
Klobušiaková, Patrícia ; Gajdoš, Martin (oponent) ; Mekyska, Jiří (vedoucí práce)
Synucleinopathy is a neurodegenerative disorder characterized by the presence of pathological protein -synuclein in neurons. So far, treatment that could heal or permanently stop this disease is not known. The aim of this work is to identify prodromal stages of synucleinopathies using functional connectivity processed applying graph metrics and assessing cortical thickness and subcortical structures volumes from magnetic resonance imaging data, and to verify specificity and sensitivity of combinations of parameters that sufficiently differentiate patients in risk of synucleinopathies. To accomplish this goal, we collected data from patients in the risk of synucleinopathy (preDLB, n = 27) and healthy controls (HC, n = 28). We found reduced volume of right pallidum and increased hippocampal volume to cortical volume ratio, increased normalised clustering coefficient and higher modularity in the preDLB group in comparison to HC. These four parameters were modeled using machine learning. The resulting model differentiated preDLB and HC with balanced accuracy of 88 %, specificity of 89 % and sensitivity of 86 %. The findings of this thesis can serve as the basis for further studies searching for specific MRI markers of prodromal stage of synucleinopathy that could be targeted with therapy in the future.
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Effect Of Intensive Dance-Exercise Intervention
On Brain Plasticity In Healthy Seniors And
Patients With Mild Cognitive Impairment
Klobušiaková, Patrícia
Intensive dance-exercise intervention leads to cortical thickening in the inferior temporal and lateral occipital cortices of the right hemisphere that are engaged in the ventral visual pathway; and to the increase in resting-state functional connectivity within the frontoparietal control network, i.e. the cognitive brain network that controls visual attention tasks. Subjects undergoing an active intervention improved in the five-point task that evaluates particularly executive functions. These findings show that 6-month intensive non-pharmacological intervention may enhance distinct brain plasticity and executive functions in a mixed cohort of healthy seniors and patients with mild cognitive impairment. Further longitudinal studies should examine whether it may also prevent/postpone cognitive decline and dementia in this population.
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