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Function of hippocampal formation in avoidance of a moving object in rat
Zitta, Pavel ; Svoboda, Jan (advisor) ; Blahna, Karel (referee)
In the last decade, there has been a significant shift in hippocampal research from static tasks to dynamic environments that better model real-life animal situations in nature. At the same time, special attention has recently been paid to inhibitory parvalbumin interneurons (PVIs) that modulate hippocampal oscillations. Therefore, the aim of this work was to investigate the role of PVIs in orientation in dynamic environments, or in behavior relative to a potential threat posed by a moving object. In this context, chemogenetic methods were used to allow experimental manipulation of PVIs. In this work, we trained transgenic PV-cre rats in a robot avoidance task. Despite intensive behavioral training, the rats appeared to learn the task only very slowly. Chemogenetic activation of PVI with substance C21 resulted only in increased locomotor activity with a stable robot. The results show that C21 does not otherwise have a major effect on rat behavior, at least not with the relatively low number of hM3Dq expressed in the PVI. Based on local potential recording (LFP) results, we further showed that PVI activation had an effect on theta frequency band power. Keywords: Behavioral task, Hippocampus, Chemogenetics, LFP, Parvalbumin, Robot
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The effect of sleep on the psychological functions of adolescents
Kaňková, Zuzana ; Nekovářová, Tereza (advisor) ; Blahna, Karel (referee)
The quality of sleep is one of the main factors for the homeostasis of the body, the functioning of the brain and therefore the psychological functions of the individual. Sleep undergoes various changes during life. Significant sleep changes can be observed in adolescents. During this developmental period, there is a shift in circadian preferences towards a later chronotype, which is often in conflict with the demands of functioning in everyday life (for example waking up to school). Because of that this group is highly vulnerable to chronic sleep restriction and associated sleep deprivation, which can lead to many pathologies. The aim of this study was to investigate the effect of partial sleep deprivation on cognitive function and emotional regulation in adolescents. The study involved 59 adolescents aged 14 to 21 years, 30 of them were exposed to partial sleep deprivation (4 hours/night) and 29 of them slept normally (8 ± 1 hours/night). The day after instructed sleep/sleep deprivation, participants completed an experimental battery of cognitive tests. The study found that adolescents after one night of partial sleep deprivation showed greater levels of subjective sleepiness than their peers after a night of normal sleep. This effect of sleep deprivation was stronger in girls than in boys. Also...
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Cognitive and behavioral alterations in neurodevelopmental and pharmacological animal models of schizophrenia
Malenínská, Kristýna ; Stuchlík, Aleš (advisor) ; Blahna, Karel (referee) ; Telenský, Petr (referee)
Establishing reliable animal models of psychiatric diseases such as schizophrenia is essential to better understand the neurobiological, behavioural and genetic basis of the disorder and to develop new drugs with greater therapeutic efficacy. These models allow the study of different aspects of schizophrenia, including positive, negative and cognitive symptoms similar to schizophrenia. All available animal models of schizophrenia can be divided into four different categories of induction: developmental, pharmacological, genetic and lesion-induced. However, none of these models perfectly replicates all aspects of schizophrenia in humans, and it is therefore necessary to precisely define the influence of each manipulation. This thesis focuses on the study of pharmacological and developmental animal models of schizophrenia, with an emphasis on examining the cognitive and behavioral changes associated with the disorder. Specifically, we investigated the pharmacological induction of schizophrenia- like symptoms by acute administration of MK-801, developmental models of two interventions combining the maternal immune response following poly(I:C) administration and subsequent stress of offspring in adolescence, and repeated prenatal and neonatal administration of lipopolysaccharide (LPS). In the...
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Ontogeny of neural mechanisms of episodic memory
Šafová, Lucie ; Nekovářová, Tereza (advisor) ; Blahna, Karel (referee)
Two brain structures in particular - the hippocampus and the prefrontal cortex (PFC) - are essential for episodic memory, the ability to recall personal experiences with details of time, place, and event. It is their developmental changes that contribute significantly to the progressive development of episodic memory. The hippocampus is a complex structure composed of several subregions that is crucial to the function of the neural basis of episodic memory. Findings show that both neuronal changes within the hippocampus and changes in its volume and the volume of hippocampal subfields influence episodic memory. As in the hippocampus, changes in the prefrontal cortex also affect episodic memory, with the PFC being among the last regions to fully mature and affecting the accuracy of recalling contextual details of episodic memories. The transfer of information between brain regions is also crucial for episodic memories, and is provided by white matter connections (fornix, cingulum, uncinate fasciculus). This thesis summarizes the knowledge about the structures and mechanisms involved in the development of episodic memory and mentions the factors that influence its development. Keywords: episodic memory, ontogeny, hippocampus, prefrontal cortex, synaptic plasticity
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Hippocampal activity during consolidation of complex spatial representations
Lavrova, Kseniia ; Kelemen, Eduard (advisor) ; Blahna, Karel (referee)
In the real world, we often need to understand complex spatial relationships and integrate existing knowledge. For example, when we learn a new route between familiar places, we need to integrate the new knowledge and create a new cognitive map of the space. Since the hippocampus is a key structure for episodic memory formation and spatial navigation, we examined the activity of hippocampal CA1 neurons when combining simple maps of a complex space. An experiment was designed, consisting of several phases, in each of which the rat was introduced to four different arms of the maze. In the first phase, the rat explored pairs of non-overlapping arms. In the second, it explored a combination of previously known arms, and in the third, all the arms of the labyrinth. During these visits, the rat had to understand the spatial relationships between the different combinations and create a complete map of the space. My results suggest that the rat was unable to understand the relationship between the independent arms before visiting the entire maze. While exploring the entire labyrinth, a completely new map for the maze was created, and there were also changes in the activity of neurons encoding already known combinations of arms. Keywords: hippocampus, sleep, remapping, place cells
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Spatial Cognition in Dynamic Environments
Blahna, Karel ; Stuchlík, Aleš (advisor) ; Syka, Josef (referee) ; Yamamotová, Anna (referee)
Innate and acquired navigational abilities of animals are often used for purposes cf study of neural mechanisms and modeling of cognitive functions. Detailed analysis of behavior allows Berger understanding of some brain structures, such as the hippocampus, entorhinal and posterior parietal cortices, and their role in these phenomena. Most of behavioral tasks involved stable environment, although the world surrounding us dynamically changes every minute. The thesis aimed at extending the knowledge of behavior of laboratory animals in mobile environments and the involvement of brain structures in processing of dynamit information.
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