Mediotemporal lobe oscillations during memory processing
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1
University of Bonn, Germany
Human declarative memory, i.e. the consciously accessible long-term memory for events and facts, crucially depends on two structures within the medial temporal lobe (MTL), the rhinal cortex and the hippocampus. Our data based on intracranial EEG recordings in presurgical epilepsy patients show that the interaction of rhinal cortex and hippocampus is crucial for declarative memory formation. We found that successful memory formation is accompanied by transient changes of phase synchronization in the gamma range between rhinal cortex and hippocampus. These memory-related synchronisation changes are interindividually correlated with increases of rhinal-hippocampal theta coherence. Compared to the waking state ongoing rhinal-hippocampal coherence decreases during sleep, which may represent an indirect electrophysiological correlate of the diminished ability to encode memories during sleep. Finally, we detected that ongoing rhinal-hippocampal coherence is more than twice as large for patients with good dream memory compared to patients with poor dream memory. These data support the idea that both, ongoing and stimulus-related rhinal-hippocampal synchronisation processes are important for long-term memory formation. Recent fMRI and clinical studies have revealed evidence that the MTL not only supports long-term memory, but also WM in case novel items or conjunctive features are processed. Indeed, we observed that slow potential shifts and phase-amplitude coupling between theta and gamma oscillations within the MTL support working memory for novel and multiple items. Our recent data furthermore suggest that the MTL represents the locus of interaction between long-term memory and working memory.
Conference:
10th International Conference on Cognitive Neuroscience, Bodrum, Türkiye, 1 Sep - 5 Sep, 2008.
Presentation Type:
Oral Presentation
Topic:
Abstracts
Citation:
Fell
J
(2008). Mediotemporal lobe oscillations during memory processing.
Conference Abstract:
10th International Conference on Cognitive Neuroscience.
doi: 10.3389/conf.neuro.09.2009.01.022
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Received:
27 Nov 2008;
Published Online:
27 Nov 2008.
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Correspondence:
Juergen Fell, University of Bonn, Bonn, Germany, juergen.fell@ukb.uni-bonn.de