Interplay of Delta and Gamma Oscillations in Thalamohippocampal Slow Gamma Synchrony in Rats with Kainic-acid Induced Hippocampal Seizures
Abstract number :
1.048
Submission category :
1. Basic Mechanisms / 1C. Electrophysiology/High frequency oscillations
Year :
2024
Submission ID :
825
Source :
www.aesnet.org
Presentation date :
12/7/2024 12:00:00 AM
Published date :
Authors :
Miao-Er Chien, MS – National Cheng Kung University
Yu-Chen Chien, MS – National Cheng Kung University
Sheng-Fu Liang, PhD – National Cheng Kung University
Chia-Chu Chiang, PhD – Case Western Reserve University
Dominique Durand, PhD – Case Western Reserve University
Presenting Author: Yi-Jen Wu, MD, PhD – National Cheng Kung University
Rationale: While hippocampus is a common seizure onset zone that can lead to focal or secondarily generalized seizures, the thalamus plays a critical role in generalized seizures and is one of the origins of delta waves. Slow gamma oscillations (25-50 Hz) have been observed in the hippocampus and thalamus with paroxysmal brief synchronizations in animals with kainic acid (KA)-induced hippocampal seizures. The mechanisms underlying slow gamma synchrony (SGS) between the hippocampus and thalamus, as well as the propagation of SGS to cortical motor areas remain unknown. This study aims to investigate the interplay of delta and gamma oscillations in thalamohippocampal SGS. We hypothesize that gamma oscillations in the hippocampus and thalamus can synchronize when the delta power of both regions is reduced.
Methods: Using a KA-induced hippocampal seizure animal model, we simultaneously recorded and analyzed local field potentials from hippocampal CA1, anterior nucleus of the thalamus (ANT), and primary motor cortex (M1) across pre-, during, and post-SGS phases.
Results: SGS was detected when gamma power in CA1 and ANT exhibited similar levels. ANT gamma power initially lagged behind CA1 but increased rapidly before SGS onset, aligning with CA1 during SGS and returning to baseline afterward. Delta power decreased during SGS in both regions, showing an inverse relationship with gamma power increase. Coherence of delta oscillations in ANT and CA1 was significantly higher than the gamma coherence, which increased before SGS, peaked at SGS, and decreased after the event. Furthermore, M1 can be recruited with SGS following CA1-ANT synchronization.
Conclusions: This study sheds light on the inverse relationship between delta and gamma oscillations in thalamohippocampal SGS, offering insights into how hippocampal seizures synchronize the thalamus and potentially lead to M1 synchronization. It also suggests the potential for therapeutic intervention in seizure synchronization by modulating the dynamics between delta and gamma oscillations.
Funding: NSTC 112-2314-B-006-061-MY3 and MOST 111-2314-B-006-100 from the National Science and Technology Council, Taiwan, and NCKUH-11210003 from the National Cheng Kung University Hospital to Dr. Yi-Jen Wu
Basic Mechanisms