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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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Role of Islet1, BDNF and nanoparticles in development, function and regeneration of the auditory system
Chumak, Tetyana ; Syka, Josef (advisor) ; Druga, Rastislav (referee) ; Maršálek, Petr (referee)
Detailed knowledge of the role that particular genes and factors play during the development and in the normal function of the auditory system is necessary to develop successful regenerative inner ear therapies. Islet1 transcription factor and brain derived neurothrophic factor (BDNF) have great potential to play a role in regenerative inner ear therapy as both have been shown to be sufficient for self-repair regeneration in cochlea in animal studies. In this study we looked at the roles these two factors play in the development and function of the auditory system. In the transgenic mice used in the study, overexpression of Isl1 affected cell specification during embryonic development, leading to enlargement of the cochleovestibular ganglion and accelerated nerve fiber extension and branching in mutant embryos. The hearing of young transgenic mice was not affected. However, it started to decline in 1-month-old animals. This early onset of age-related hearing loss was found to be a consequence of the neurodegeneration of the olivocochlear system caused by Pax2-driven Isl1 misexpression in the hindbrain. Our data provide the first evidence that the alternation of the olivocochlear system efferent system accelerates the age-related functional decline of hearing without the loss of OHCs. The functional role of...
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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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Role of Islet1, BDNF and nanoparticles in development, function and regeneration of the auditory system
Chumak, Tetyana ; Syka, Josef (advisor) ; Druga, Rastislav (referee) ; Maršálek, Petr (referee)
Detailed knowledge of the role that particular genes and factors play during the development and in the normal function of the auditory system is necessary to develop successful regenerative inner ear therapies. Islet1 transcription factor and brain derived neurothrophic factor (BDNF) have great potential to play a role in regenerative inner ear therapy as both have been shown to be sufficient for self-repair regeneration in cochlea in animal studies. In this study we looked at the roles these two factors play in the development and function of the auditory system. In the transgenic mice used in the study, overexpression of Isl1 affected cell specification during embryonic development, leading to enlargement of the cochleovestibular ganglion and accelerated nerve fiber extension and branching in mutant embryos. The hearing of young transgenic mice was not affected. However, it started to decline in 1-month-old animals. This early onset of age-related hearing loss was found to be a consequence of the neurodegeneration of the olivocochlear system caused by Pax2-driven Isl1 misexpression in the hindbrain. Our data provide the first evidence that the alternation of the olivocochlear system efferent system accelerates the age-related functional decline of hearing without the loss of OHCs. The functional role of...
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Volumetry and laterality of CNS structures in animal experiments and in human (in health and disease)
Mrzílková, Jana ; Zach, Petr (advisor) ; Syka, Josef (referee) ; Novotný, Jiří (referee)
Our work is composed of part done on laboratory rat, part done on magnetic resonance images and autoptic CNS tissue in patients with Alzheimer's disease (AD) and control group. In the first part we observed volumetrically and stereologically morphological, right-left asymmetries of structures of CNS, gross marks of neurodegeneration and changes in the number of neurons and conditioned taste aversion (hippocampus, prefrontal cortex, parabrachial nucleus, amygdalar complex). We measured under normal conditions and under chronic stress induced by corticosterone. Chronic stress is possible candidate for AD development in humans. We found that structural lesion is side specific (on the right) and it is bound rather to subcellular level and not to absolute neuronal numbers changes. In the second part we examined changes in the grey matter of the CNS (by automatic segmentation and manually) and changes in the white matter of the CNS (tractography) in patients with AD and in controls on magnetic resonance. In the autoptic tissue we focused on asymmetrical morphological changes in the planum temporale and neurohistological changes in its third neuronal layer. We found out that decrease of the hippocampal volume is not accompanied by cerebellar or pontine volume and that reorientation of images is not necessary for...
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Organization of the auditory cortex and changes in the auditory system in presbycusis.
Profant, Oliver ; Syka, Josef (advisor) ; Vymazal, Josef (referee) ; Chrobok, Viktor (referee)
2. Abstract The aim of my study was to identify specific features of the structure and function of neurons in the auditory cortex of rat and to analyze age-related changes in the inhibitory system (GAD 65 and 67) in the central auditory structures of the same species. Based on the findings in the animal model we focused on changes in the central part of the auditory pathway and auditory cortex in aging human population that were examined by various MRI techniques (spectroscopy, morphometry, diffusion tensor imaging and functional MRI). We found that the most significant feature of neurons in the auditory cortex is the presence of the hyperpolarization-activated cation current that influences functional properties of neurons. The differences among neurons in different fields of the AC were based on their specific functional characteristics, with the tonotopy being the key factor of the AC structural organization. Aging of the auditory system has a negative influence on the speech understanding in which the processing of temporal parameters of the sound plays a significant role. In animal experiments we observed decreases of the enzymes GAD65 and 67 (that catalyze synthesis of the main inhibitory neurotransmitter GABA) in central parts of the auditory system. Inhibition is the key factor in coding and...
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Music physiology, ergonomics and physical therapy in the health promotion, prevention and treatment of the playing related musculoskeletal disorders by musicians and its applicationin in the music education
Vencel, Miroslav ; Tichá, Alena (advisor) ; Tichá, Libuše (referee) ; Syka, Josef (referee)
The aim of this thesis is to describe the current state of knowledge and research on music physiology. The information on music physiology and musician`s medicine, ergonomics, physical therapy and neuroscience of music is presented with regard to its pedagogical use, with the goal of prevention and treatment of playing related musculoskeletal disorders in musicians. The creation of the good movement habits is considered for useful prevention. Therefore, a method of compensatory exercises is being developed, which was verified in the experimental part of this work. Positive influence of the therapy of postural disorders by means of the ontogenetical kinesiology and yoga came up to our expectations. In the didactic part we introduce educational programms aiming at better understanding of music physiology and training in using exercises in the self-treatment. KEYWORDS: music physiology, musician`s medicine, prevention and treatment of the playing related musculoskeletal disorders, ergonomics and neuroscience of music, compensatory exercises and movement stereotypes reeducation, professional music education
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Spatial cognition in rats: processing of information about the position of distant object
Levčík, David ; Klement, Daniel (advisor) ; Syka, Josef (referee) ; Hort, Jakub (referee)
Spatial behavior is widely studied to understand cognition and its neurophysiological substrate. Hippocampus plays a crucial role in many spatial tasks. It is unclear whether hippocampus is necessary for recognizing position of distant objects located in inaccessible space. To address this question we developed a novel operant-conditioning task in which rats recognize position of an object located in an inaccessible space. We assessed the role of the dorsal hippocampus in the task by blocking its activity with muscimol. Our results showed that intact rats use the dorsal hippocampus for recognizing position of the distant object located in the inaccessible part of the environment. In addition, we showed that the cognitive performance in the task is not affected by the changes in motor activity induced by prazosin. Key words: spatial cognition, operant conditioning, hippocampus, muscimol, prazosin
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