Thesis supervisor: Lucia Wittner
Location of studies (in Hungarian): Semmelweis Egyetem Abbreviation of location of studies: SE
Description of the research topic:
Sharp-wave ripple complexes (SPW-Rs) are irregular activities on the hippocampal electroencephalogram, during slow wave sleep and wake immobility. These synchronous population events are thought to have an important role in memory consolidation and in the generation of long-term memory engrams. The hippocampus, due to its special anatomical structure, is prone to generate and transfer memory traces, such as pathological synchronies, such as epileptic seizures. The information flow between the different regions of the hippocampus during SPW-Rs and epileptic seizures are not fully understood. In this project we wish to examine the spreading of these synchronous activities in a rat in vitro model of SPW-Rs as well as in pharmacologically induced seizure model. Based on the classical trisynaptic loop hypothesis, the information flows from the dentate gyrus (DG) to the CA3 region, and transfers the memory traces towards the CA1 region and to extrahippocampal territories. Our preliminary data shows however, that SPW-Rs can be simultaneously generated in both the DG and the CA3 region, or in the CA3 region and spread to the DG or vice versa, and we saw cases when either one or the other region showed SPW-R activity. We would like to explore the spreading mechanisms of SPW-Rs as well as those of epileptic seizures induced by Mg2+-free solution. Furthermore, we aim to examine the role of the different neuron types of the DG and the CA3 region in the generation of these synchronous events. The activity of the excitatory and inhibitory cell types can be increased and decreased using pharmacological agents, and thus, we can reveal their special role in the emergence and transfer of SPW-Rs and epileptic seizures. The inverse direction of the information propagation may provide an extra loop in the hippocampal trisynaptic loop, which might amplify the memory engrams for a more efficient memory consolidation. The knowledge about the spread of epileptic seizures can afford for intervention points for a future new therapy.
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