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Learning-enhanced coupling between ripple oscillations in association cortices and hippocampus
Dion Khodagholy1,2, Jennifer N Gelinas1,3,4, György Buzsáki1
1NYU Neuroscience Institute, School of Medicine, New York University, New York, NY 10016, USA.
Science (New York, N.Y.)
|October 21, 2017
Summary
Memory consolidation involves hippocampal-neocortical communication. This study reveals that ripple-ripple coupling between the hippocampus and specific cortical areas during sleep supports memory transfer.
Area of Science:
- Neuroscience
- Memory Consolidation
- Systems Neuroscience
Background:
- Declarative memory consolidation relies on communication between the hippocampus and neocortex.
- The precise cortical targets and mechanisms for hippocampal information transfer remain unclear.
Purpose of the Study:
- To investigate the cortical destinations and physiological patterns of hippocampal information transfer during memory consolidation.
- To identify the role of neural oscillations in mediating hippocampal-neocortical communication.
Main Methods:
- Utilized a conformable microelectrode array (NeuroGrid) for dorsal cortical recordings in rats.
- Simultaneously performed silicon probe recordings in the hippocampus.
- Analyzed local field potentials and neural spiking during sleep, focusing on ripple oscillations (100-150 Hz).
Main Results:
- Localized ripple oscillations were observed in parietal, midline, and prefrontal cortical areas during sleep, concurrent with hippocampal ripples.
- These ripple events were absent in primary cortical areas.
- Hippocampal-neocortical ripple coupling intensified after learning during sleep.
Conclusions:
- Findings suggest that ripple-ripple coupling facilitates the transfer of memory traces from the hippocampus to association cortices.
- This mechanism is crucial for declarative memory consolidation.
- Identified specific cortical regions involved in hippocampal memory transfer.
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