Related Experiment Video
Updated: Jun 20, 2026
07:33
Optogenetic Entrainment of Hippocampal Theta Oscillations in Behaving Mice
Published on: June 29, 2018
Slow oscillation electrical brain stimulation during waking promotes EEG theta activity and memory encoding
Roumen Kirov1, Carsten Weiss, Hartwig R Siebner
1Department of Neuroendocrinology, University of Lübeck, 23538 Lübeck, Germany.
Summary
Transcranial slow oscillation stimulation (tSOS) enhances brain oscillations and memory. Applied during wakefulness, tSOS boosts theta activity and improves memory encoding, unlike during sleep when it aids memory consolidation.
Area of Science:
- Neuroscience
- Cognitive Science
Background:
- Transcranial slow oscillation stimulation (tSOS) at 0.75 Hz enhances slow oscillatory activity and memory consolidation during sleep.
- The effects of tSOS on brain activity and memory during wakefulness remain less understood.
Purpose of the Study:
- To investigate the impact of tSOS on endogenous electroencephalogram (EEG) oscillations during wakefulness.
- To examine the effects of tSOS on hippocampus-dependent memory encoding and consolidation when applied during learning or after learning in the waking state.
Main Methods:
- Application of tSOS (0.75 Hz) during wakefulness.
- Analysis of EEG recordings to measure slow oscillations (0.4-1.2 Hz) and theta activity (4-8 Hz).
- Assessment of memory consolidation and encoding using hippocampus-dependent memory tasks.
Main Results:
- tSOS applied during wakefulness increased endogenous EEG slow oscillations in a restricted manner.
- tSOS during wakefulness led to a widespread increase in EEG theta activity.
- tSOS did not enhance memory consolidation when applied post-learning but improved memory encoding when applied during learning.
Conclusions:
- The brain state critically influences the EEG frequency and memory processes affected by tSOS.
- During wakefulness, tSOS elicits a preferential response in theta oscillations, facilitating memory encoding.
