Untersuchung des hippokampo-neokortikalen Dialogs im deklarativen Gedächtnis mittels funktioneller Magnetresonanztomographie (fMRT)

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Memory for facts and events, i.e. declarative memory, relies mainly on two brain structures: the hippocampus and the neocortex. Numerous studies have shown that acquisition and retrieval of new declarative memories depends on the hippocainpus. After some time, however, the memory trace becomes independent of it, indicating some kind of information transfer. Recently, the irnportance of sleep for this transfer of the memory trace has been discussed extensively. Especially slow-wave sleep is thought to drive this information transfer by reactivation of those neuronal networks that were active during learning. The experiments described here are aimed at finding correlates of this hippocampal-neocortical dialogue in human brain activity. The studies in phase I look at changes in hippocampal and neocortical activity during word list recall after sleep as compared to recall after periods of wakefulness. In addition, the dynamics of the hippocampal-neocortical information transfer will be modified experimentally by pharmacological manipulation of cholinergic neurotransmission. Activity will be recorded by means of fMRI and electroencephalography (EEG) recording. In phase II, brain activity during sleep will also be recorded to provide direct evidence for the model of a hippocampal-neocortical dialogue in humans.