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Arachnophobia and the cause of fear of spiders
Říha, Roman ; Dolejš, Petr (advisor) ; Vlček, Kamil (referee)
Fear of spiders is largely widespread, and in some cases may even grow into a phobia. Negative attitude towards spiders can be found already in the mythology of some peoples. This attitude is often in the Western culture. It is interesting that this fear persists even though there are very few spiders which are able to endanger human life. There are more possible causes of arachnophobia, including classical conditioning, information transmission and impact of disgust emotions. Right the disgust seems to be the probable explanation of spider phobia. Relevance fear is documented by a list of dangerous spiders to humans. Some spiders are in fact able to endanger human health by toxins contained in their venom. Basic questions to deal with are validity of human fear of spiders and possible causes of this negative relationship.
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Virtual environments as a tool to study human navigation
Hejtmánek, Lukáš ; Vlček, Kamil (advisor) ; Maršálek, Petr (referee) ; Brom, Cyril (referee)
Navigation is one of the most common forms of cognitive processing, which is natural for all animal species. But the neuroscientific inquiry into navigation in human subjects has been hindered by the requirements of monitoring methods, which usually require subjects to be com- pletely still. Virtual environments allow scientists to study navigation even while the subject remains unmoving, and offer other benefits such as full control over the experimental procedures or precise behavioral recordings. This thesis offers a basic overview of the biology of navigation and presents why navigation is an interesting cognitive process to investigate. It then presents virtual environments, explores how they can help neuroscientists to study navigation and outlines their limitations. Lastly, the literary review tries to address the question if navigation in virtual environments is comparable to navigation in the real world. The empirical part presents five original studies of human navigation and virtual environ- ments. These studies focus on differences of real world and virtual navigation, investigate neural pathways and brain regions involved in spatial processing, and offer examples of how virtual environments can help conduct studies otherwise impossible to do in the real world. One study provides an...
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Spatial memory in humans and its disorders: From animal models towards schizophrenia
Fajnerová, Iveta ; Vlček, Kamil (advisor) ; Rokyta, Richard (referee) ; Jiruška, Přemysl (referee)
Spatial memory is often studied using spatial tasks originally developed for animals, such as the Morris water maze and the Carousel maze tasks. Both tasks have an important role in the process of identification of brain areas crucial for spatial memory, and also in pharmacological research of animal models of neuropsychiatric diseases. In recent years considerable attention has been devoted to the research and treatment of cognitive impairment in schizophrenia. Comparative research addressing cognitive abilities of both animals and patients in similar tasks, could therefore lead to verification of the predictive and face validity of animal models of this complex disorder. The aim of this study was to create virtual analogues of these tasks, which would allow this comparative approach. This thesis first describes the experiment testing the performance of an animal model of schizophrenia induced by the application of dizocilpine (MK-801) in reversal version of both mentioned spatial tasks, in order to assess mental flexibility and learning abilities affected in schizophrenia. Other two experiments present the findings of the two virtual analogues tested in the first episode of schizophrenia patients. Our results confirm the presence of deficits in spatial memory and mental flexibility, functions dependent on...
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EEG correlates of egocentric and allocentric distance estimates in virtual environment in humans
Kalinová, Jana ; Vlček, Kamil (advisor) ; Telenský, Petr (referee)
Cognitive processes associated with spatial orientation can use different reference frames: egocentric, centered on observer and allocentric, centered on objects in the environment. In this thesis, we use EEG to investigate the dynamics of brain processes accompanying spatial orientation based on these reference frames. Participants were instructed to estimate distances between objects or themselves and objects located in a virtual circular arena; this task was presented in both 2D and 3D displays. Task-related EEG changes were analyzed using a time-frequency analysis and event-related potential analysis of 128-channel EEG recordings. Through time-frequency analysis we found significant power differences in delta, theta, alpha, beta and gamma bands amongst the control, egocentric and allocentric testing conditions. We noted a decrease in alpha power in occipital and parietal regions, while a significantly stronger decrease was observed for the allocentric condition compared to both egocentric and control conditions. A similar pattern was also detectable for the beta band. We also report an increase in theta and delta power in temporal, fronto-temporal and lateral frontal regions that was significantly stronger for the egocentric condition compared to control and, in some electrodes, even...
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Psychophysiological correlates of emotion and memory
Jindrová, Miroslava ; Telenský, Petr (advisor) ; Vlček, Kamil (referee)
The first aim was to determine the baseline psychophysiological correlates in healthy subjects as a first necessary step towards the long-term goal of application the psychophysiological techniques in diagnostics mood and cognitive disorders. The second aim was to establish an easily applicable set of tests for evaluating emotional and memory processes by non-invasive psychophysiological methods. EEG, GSR, and eye-tracking data from 100 participants without any neurological or psychiatric disorders were obtained during watching affective pictures and performing memory tests. The spectral powers were computed for each 500 ms of the stimuli in theta, alpha, beta1, beta2 and beta3 bands in 12 areas of the brain. Lower alpha and higher beta3 power was related to higher emotional intensity. Negative emotions were distinguished in spatio-temporal changes of beta1 power and positive emotions showed higher beta3 power in right temporal region. Memory encoding showed higher alpha power. Lower theta and higher alpha power in central regions and overall increase of beta bands were observed during successful memory retrieval. A summary of spatio-temporal spectral correlates to emotional and memory processes was provided by this work. Key words: Electroencephalography, electrodermal activity, psychophysiology,...
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Comparison of episodic memory research approaches in human, from the viewpoint of cognitive psychology and neuroscience.
Kočí, Markéta ; Vlček, Kamil (advisor) ; Červená, Kateřina (referee)
Episodic memory allows a person to recall events of one's personal past. During the retrieval, memory is re-experienced as a vivid imaginary experience, accompanied by a rich temporo-spatial context and autonoetic consciousness - awareness of the self. Further episodic memory characteristics are captured in its several models. Some of them focus on the encoding, consolidation and retrieval processes, other on the spatial context, time duration of events, autobiographical context or characteristic feelings during retrieval. The models differ in some aspects and converge in other aspects, and given together they provide general view on episodic memory approaches.
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