Odor-induced modification of oscillations and related theta-higher gamma coupling in olfactory bulb neurons of awake and anesthetized rats

Ping Zhu; Shuge Liu; Yulan Tian; Yating Chen; Wei Chen; Ping Wang; Liping Du; Chunsheng Wu

doi:10.3389/fchem.2022.865006

Odor-induced modification of oscillations and related theta-higher gamma coupling in olfactory bulb neurons of awake and anesthetized rats

Front Chem. 2022 Aug 1:10:865006. doi: 10.3389/fchem.2022.865006. eCollection 2022.

Authors

Ping Zhu^{1

2}, Shuge Liu^{1

2}, Yulan Tian^{1

2}, Yating Chen^{1

2}, Wei Chen^{1

2}, Ping Wang^{3

4}, Liping Du^{1

2

3

4}, Chunsheng Wu^{1

2}

Affiliations

¹ Department of Biophysics, Health Science Center, Institute of Medical Engineering, School of Basic Medical Sciences, Xi'an Jiaotong University, Xi'an, China.
² Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education of China, Xi'an Jiaotong University, Xi'an, China.
³ Biosensor National Special Laboratory, Department of Biomedical Engineering, Zhejiang University, Hangzhou, China.
⁴ Key Laboratory for Biomedical Engineering of Ministry of Education, Department of Biomedical Engineering, Zhejiang University, Hangzhou, China.

Abstract

Olfactory gamma oscillations (40-100 Hz) are generated spontaneously in animals and represent the activity of local olfactory bulb (OB) networks, which play important roles in cognitive mechanisms. In addition, high-frequency oscillations (HFO, 130-180 Hz) have attracted widespread attention and are novel neuronal oscillations with a frequency range closer to high gamma oscillations (60-100 Hz, HGOs). Both HGOs and HFOs are distinctly regulated by θ rhythm in the hippocampus. To understand their mediation mechanisms in the OB, we investigated whether local field potential (LFP) oscillations including HGOs and HFOs and even their coupling with theta rhythm are modified by odor stimulation in both freely moving and anesthetized rats. Therefore, we combined electrophysiological technology and cross-frequency coupling analysis approaches to determine the difference in the odor-modulated LFP oscillations between awake and anesthetized rats. The obtained results indicate that LFP oscillations including HGOs and HFOs were differently modified by odor stimulation in animals of both states. However, θ-HGO and θ-HFO coupling were modified in only awake animals. It is suggested that these oscillations and their interactions with theta oscillations may play crucial roles in olfactory network activity. This could pave the way for further understanding the underlying mechanisms of oscillations in OB neurons towards odor sensation.

Keywords: cross-frequency coupling; high gamma; high-frequency oscillations; neuronal oscillations; odor stimulation.