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Updated: Jun 2, 2026
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Optogenetic Entrainment of Hippocampal Theta Oscillations in Behaving Mice
Published on: June 29, 2018
Greater running speeds result in altered hippocampal phase sequence dynamics
Andrew P Maurer1, Sara N Burke, Peter Lipa
1Evelyn F. McKnight Brain Institute, Tucson, Arizona, USA.
Hippocampus
|May 4, 2011
Summary
Hippocampal networks predict future events by activating cell assemblies in a "phase sequence." This "look ahead" mechanism accelerates as running speed increases, representing upcoming locations.
Area of Science:
- Neuroscience
- Computational Neuroscience
- Behavioral Neuroscience
Background:
- Hebb's "phase sequence" describes sequential activation of cell assemblies.
- Hippocampal cell assemblies are groups of coactive neurons with overlapping place fields.
- Phase sequences in the hippocampus involve changing assembly membership during navigation.
Purpose of the Study:
- To investigate the "look ahead" mechanism in hippocampal phase sequences.
- To determine how running velocity affects the composition of hippocampal phase sequences.
- To test the hypothesis that hippocampal networks predict future events.
Main Methods:
- Utilized a population vector-based reconstruction method to capture network activity.
- Recorded neural activity in the hippocampus of rats during locomotion.
- Analyzed changes in cell assembly composition within theta cycles at varying speeds.
Main Results:
- The composition of hippocampal phase sequences systematically changes with running velocity.
- A higher number of cell assemblies are active within a single theta cycle at increased speeds.
- This "look ahead" activity transiently represents locations in front of the animal.
Conclusions:
- Hippocampal networks exhibit velocity-dependent "look ahead" activity.
- These findings support the role of hippocampal networks in generating short-term predictions.
- Such predictions are crucial for optimizing animal behavior and navigation.
