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Somatomotor and somatosensory modulation of pain in the EEG and fMR image
Vrána, Jiří ; Stančák, Andrej (advisor) ; Vymazal, Josef (referee) ; Jech, Robert (referee) ; Hájek, Milan (referee)
Pain processing is modulated at different levels of the central nervous system by concurrent sensory and motor processes. From previous studies with innocuous somatosensory evoked potentials we know of the phenomenon of gating by movement. The classical explanation [Melzack R, Wall PD. Pain mechanisms: a new theory. Science 1965;150(699):971-979.] of the mechanism of gating in the posterior horn of spinal cord is complemented by other, lesser understood data, suggesting supraspinal mechanisms. A similar lack of understanding of the cortical mechanisms is seen in pain modulating methods using concurrent electrical nerve stimulation. This work is intended to further our understanding of the cortical mechanisms of pain modulation in the specific cases of (a) isometric muscle contraction of the right or left hand during painful electrical intraepidermal stimulation of the right index finger and (b) during observation of the acute effects of concurrent innocuous median nerve stimulation on painful tonic thermal stimulation of the thenar eminence.
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Improving the diagnosis of first-episode schizophrenia from magnetic resonance imaging using machine learning
Mikoláš, Pavol ; Hájek, Tomáš (advisor) ; Syka, Josef (referee) ; Hájek, Milan (referee)
Background: Early diagnosis of schizophrenia could improve the outcomes and limit the negative effects of untreated illness. Although participants with schizophrenia show structural/functional alterations on the group level, these findings have a limited diagnostic utility. Novel methods of MRI analyses, such as machine learning (ML), may help bring neuroimaging from bench to the bedside. Here, we used ML to differentiate participants with a first episode of schizophrenia-spectrum disorder (FES) from healthy controls (HC) based on neuroimaging data and compared the diagnostic utility of such approach with the utility of between group comparisons using classical statistical methods. Method: Firstly, we performed a classical fMRI experiment in FES using a self/other- agency task (SA/OA) and compared FES (N=35) versus controls (N=35) using conventional statistics. We than classified FES and healthy controls (HC) using linear kernel support vector machine (SVM) from the resting-state functional connectivity (rsFC) and fractional anisotropy (FA) in 63/63 and 77/77 age- and sex-matched FES and HC participants. We also investigated the between-group differences in rsFC and FA using classical between-group comparisons. Results: FES group exhibited a decreased activation during the emergent SA experience...
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New Neurophysiological Indicators Measuring, Monitoring and Evaluating in Selected Psychiatric Disorders
Šóš, Peter ; Höschl, Cyril (advisor) ; Libiger, Jan (referee) ; Hájek, Milan (referee)
There is increasing amount of new knowledge in neuropsychiatric research, partially as a result of application of new neurophysiological methods of quantitative electroencephalography. This is because these techniques have good temporal resolution, are relatively non-invasive and economical. Different experimental paradigms and electroencephalographical analytical techniques are reviewed, with their potential applications in the assessment of psychiatric disorders. In the theoretical part the principles of some methods of quantitative electroencephalography, especially are described: EEG coherences, QEEG cordance and LORETA. Next chapter contains basic information about panic disorder and major depressive disorder followed by findings in functional imaging studies which are associated with the selected psychiatric disorders. Separate section is devoted to the prediction of antidepressant response. The empirical part of the thesis consists of a set of the five original papers about application of QEEG methods in a population of psychiatric patients (Bareš et al., 2010; Kopeček et al., 2008; Kopřivová et al., 2009; Šóš et al., 2008; Šóš et al., 2013). In Study 1, we followed the localization of EEG sources by means of brain electromagnetic tomography with low resolution (LORETA) in patients with panic...
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31P MR Spectroscopy of Human Kidney Grafts Monitoring of MR parameters of human grafts and their comparison with clinical parameters of patients
Vyhnanovská, Pavlína ; Hájek, Milan (advisor) ; Teplan, Vladimír (referee) ; Mechl, Marek (referee)
The aim of this work was to evaluate the possibility of using in vivo phosphorus magnetic resonance spectroscopy (31P MRS) for diagnosis of kidney graft dysfunction after transplantation. In vivo 31P MRS is noninvasive imaging method which make possible to assess energy metabolism. A total of 68 patients with kidney grafts were examined on a 1.5T MR scanner. 31P MRS was performed using the 2D-chemical shift imaging method. The patients were divided into four groups: acute rejection; acute tubular necrosis; late graft dysfunction; and patients with good renal function after transplantation. We measured the signal intensities of phosphomonoesters (PME), inorganic phosphate (Pi), phosphodiesters (PDE) and -, -- adenosine triphosphate (with contribution of -, -adenosine diphosphate) and their ratios. Patients with acute rejection episodes showed significantly elevated PME/ß-ATP, PME/Pi and PDE/Pi signal ratios compared to the control group. The group with acute tubular necrosis has decreased these ratios: PDE/-ATP a PDE/Pi compared to the control group. Patients with late graft dysfunction revealed only significant decrease of PME/Pi ratio. The group of AR patients display higher ratios of PME/Pi and PDE/Pi compared to the group of ATN patients and display higher ratios of PME/Pi compared to the group of LGD....
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Treatment of spinal cord injury targetting secondary mechanisms
Valášková, Barbora ; Jendelová, Pavla (advisor) ; Hájek, Milan (referee) ; Rokyta, Richard (referee)
1 Abstract Traumatic spinal cord injury (SCI) is severe condition with devastating long- lasting consequences. There is still no available treatment. After initialing mechanical trauma, there is a huge cascade of secondary reactions which amplifies the damage. This thesis is focused on potential therapeutic effect of photobiomodulation, natural anti- inflammatory compounds epigallocatechin-3-gallate (EGCG), curcumin, their combination and extrapure synthetic form of curcumin called "nanocurcumin" on impacts of experimental model of SCI in rats. Photobiomodulation using combination of two synchronized wavelengths 808 and 905 nm improved functional recovery after SCI evaluated by battery of locomotor tests and somatosensory plantar test. The group treated by photobiomodulation obtain better results in all tests. The histopathological analysis showed a positive effect on white and gray matter sparing and our data suggests an upregulation of M2 microglia/macrophages in photobiomodulation treated rats assessed by immunohistochemical and RT-qPCR analysis. Our results demonstrated that the photobiomodulation is a promising non-invasive therapy for improving functional recovery and tissue sparing after SCI. EGCG and curcumin are natural compounds known in Chinese medicine for centuries. Their neuroprotective and...
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Improving the diagnosis of first-episode schizophrenia from magnetic resonance imaging using machine learning
Mikoláš, Pavol ; Hájek, Tomáš (advisor) ; Syka, Josef (referee) ; Hájek, Milan (referee)
Background: Early diagnosis of schizophrenia could improve the outcomes and limit the negative effects of untreated illness. Although participants with schizophrenia show structural/functional alterations on the group level, these findings have a limited diagnostic utility. Novel methods of MRI analyses, such as machine learning (ML), may help bring neuroimaging from bench to the bedside. Here, we used ML to differentiate participants with a first episode of schizophrenia-spectrum disorder (FES) from healthy controls (HC) based on neuroimaging data and compared the diagnostic utility of such approach with the utility of between group comparisons using classical statistical methods. Method: Firstly, we performed a classical fMRI experiment in FES using a self/other- agency task (SA/OA) and compared FES (N=35) versus controls (N=35) using conventional statistics. We than classified FES and healthy controls (HC) using linear kernel support vector machine (SVM) from the resting-state functional connectivity (rsFC) and fractional anisotropy (FA) in 63/63 and 77/77 age- and sex-matched FES and HC participants. We also investigated the between-group differences in rsFC and FA using classical between-group comparisons. Results: FES group exhibited a decreased activation during the emergent SA experience...
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MR imaging and MR spectroscopy of human during physical stress (MR spectroscopy imaging, MR diffusometry, MR relaxometry etc.)
Šedivý, Petr ; Hájek, Milan (advisor) ; Haberlová, Jana (referee) ; Vymazal, Josef (referee)
The dissertation is concerned to in vivo phosphorus MR spectroscopy (31 P MRS) and 1 H MR imaging (MRI) of muscle in combination with physical workload. The theoretical part of the thesis describes methodology of 31 P MRS measurement and its clinical use in research of metabolic changes in diabetes, heart failure and peripheral artery disease (PAD). The results of the thesis are divided into methodical and clinical parts. Methodical results deal with the construction of experimental equipment, software modification and development, and show of the reproducibility of the dynamic 31 P MRS. The MRI after exercise was used to the describe involvement of the individual calf muscles to muscle contraction during pedal movement in MR compatible ergometer. The first part of the clinical results of the thesis describes changes in muscle metabolism during diabetes and critical ischemia. In patients with critical ischemia the effect of treatment by angioplasty or transplantation of mesenchymal stem cells was evaluated. In the second part of the clinical results the metabolism of patients with heart failure complicated by sideropenia was studied. In these patients the effect of experimental treatment by iron carboxymaltose was described.
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Analysis of value of functional neuroimaging methods in diagnostics of focal intractable epilepsy
Kudr, Martin ; Kršek, Pavel (advisor) ; Brázdil, Milan (referee) ; Hájek, Milan (referee)
Epilepsy is one of the most common neurological disorders with prevalence 0,5 to 1 %. Considerable number of patients (particularly children) suffers from intractable focal epilepsy caused by focal cortical dysplasia (FCD) - a localized malformation of cortical development. The only treatment option in these patients remains resective epilepsy surgery. Its goal is to remove the epileptogenic zone (EZ) defined as the area of the cerebral cortex that is indispensable for the generation of epileptic seizures. There is currently no exclusive diagnostic test for localizing EZ localization; the localization hypothesis is based on combination of more diagnostic methods. Neuroimaging methods (especially magnetic resonance imaging - MRI) are crucial for localizing EZ; however, functional neuroimaging methods analyzing different functional aspects of the brain tissue can be equally important. The goal of this PhD study is to analyze value of functional neuroimaging methods (especially SPECT and SISCOM respectively and FDG-PET) for the EZ localization in patients with focal intractable epilepsy. In the first presented study we analyzed value of ictal SPECT examination for the EZ localization in a large cohort of pediatric patients with FCD operated on in Miami Children's Hospital, Florida. The study proved that...
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