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Optogenetic Entrainment of Hippocampal Theta Oscillations in Behaving Mice
Published on: June 29, 2018
Ketamine alters oscillatory coupling in the hippocampus
Fábio V Caixeta1, Alianda M Cornélio, Robson Scheffer-Teixeira
1Brain Institute, Federal University of Rio Grande do Norte, Natal, RN 59056-450, Brazil.
Scientific Reports
|August 3, 2013
Summary
Ketamine disrupts brain oscillations crucial for cognitive functions. This study reveals how ketamine alters hippocampal network interactions, specifically theta-gamma coupling, offering insights into schizophrenia models.
Area of Science:
- Neuroscience
- Computational Neuroscience
Background:
- Higher-order oscillatory interactions, like cross-frequency coupling, are vital for cognitive functions such as perception, attention, and memory.
- Schizophrenia is characterized by impairments in these cognitive functions.
Purpose of the Study:
- To investigate the effects of ketamine, a pharmacological model of schizophrenia, on hippocampal oscillatory coupling dynamics in awake rats.
- To examine how ketamine administration alters phase coherence and phase-amplitude coupling within the hippocampus.
Main Methods:
- Administration of ketamine (25, 50, and 75 mg/kg i.p.) to awake rats.
- Electrophysiological recordings across different hippocampal layers (CA1-dentate axis).
- Analysis of theta, delta, gamma, and high-frequency oscillations (HFO) power, phase coherence, and phase-amplitude coupling.
Main Results:
- Ketamine increased gamma and HFO power across hippocampal depths.
- Phase coherence of gamma and HFO oscillations increased between hippocampal layers.
- Phase-amplitude coupling between theta and fast oscillations was dose-dependently altered: theta-HFO coupling increased, while theta-gamma coupling was enhanced at low doses and disrupted at high doses.
Conclusions:
- Ketamine significantly alters hippocampal network interactions.
- The study demonstrates that ketamine disrupts cognitively relevant theta-gamma coupling in a dose-dependent manner.
- These findings provide insights into the neurophysiological mechanisms underlying schizophrenia.
