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Hippocampus and consolidation of contextual memory in physiological and pathological conditions
Taskina, Sofia ; Kelemen, Eduard (advisor) ; Vlček, Kamil (referee)
afa Contextual memory and context processing are important brain abilities for learning, adap- tation, and overall life. This work aims to understand what these abilities are, what structures and processes support them, and the pathologies associated with them. Such an approach will allow evaluating the significance of contextual memory, understanding how it arises, changes, is retrieved, and forgotten, and also identifying to what extent further discoveries in this field will contribute to the development of treatments for disorders in which contextual processing has undergone alterations. afa Key words: contextual memory, contextual processing, hippocampus, memory consolida- tion, PTSD
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Brain Oscillations and Temporal Structure of Spatial Memory Pattern Retrieval
Zitrický, František ; Ježek, Karel (advisor) ; Kelemen, Eduard (referee) ; Vlček, Kamil (referee)
The hippocampus is a brain structure essentially involved in episodic memory, spatial navigation and other complex cognitive functions. The distinct network architecture of hippocampal CA3 allows to combine converging sensory inputs in creation of complex neural representations. The hippocampus further interacts with the entorhinal cortex to organize knowledge into relational representations, also known as 'cognitive maps'. In rodents, the hippocampal pyramidal neurons behave as place cells, where a neuron is active whenever the subject occupies specific location in the environment. The collective activity of the place cells represents a neural map that is reinstated during repeated exploration of the same space. The place cell maps are thus recognized as neural substrate of spatial memory. In this work, we aimed at better understanding of hippocampal CA3 network dynamics during period of reinstatement of the appropriate place cell representation. We thus analysed CA3 place cell activity recorded during 'teleportation' experiment, where the rats are exposed to abrupt changes in spatial context identity. As shown previously, the network state transitions involve short competitive period, where network state quickly switches between the representations of the previous and the present environment. We...
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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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Abstract tasks in birds - spatial vs non-spatial tasks
Janská, Iveta ; Landová, Eva (advisor) ; Vlček, Kamil (referee)
The aim of this thesis is to compare spatial cognitive tasks (radial maze and analogs, geometry and features) and non-spatial abstract cognitive task (concept formation and categorization, transitive inference) in birds. Because each of tasks have different testing methods they are compared according to method types in separate thematic groups, which are discussed each other. The extension of this thesis on theories derived from human psychology such as self-recognition, episodic-like memory, and theory of mind.
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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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