Odor Induced Modification of Oscillations and Related Theta-Higher Gamma Coupling in Olfactory Bulb Neurons of Awake Rats

Olfactory gamma oscillations (40–100 Hz) are generated spontaneously in awake animals, and represent the activity of local OB networks, which play important roles in cognitive mechanisms. In addition, high-frequency oscillations (HFO, 130–180 Hz) has also attracted widespread attention, which is a novel neuronal oscillation with a frequency range close to high gamma (HG) oscillations. Both of two oscillations are distinctly regulated by theta rhythm in the hippocampus. In order to understand their mediation mechanisms in the OB, we testes whether HG and HFOs, and even their coupling with theta rhythm are modified by odor stimulation in freely-moving rats by combining electrophysiological and cross-frequency coupling analysis approaches. The obtained results indicate that HG and HFOs and their theta phase-locked coupling were differently modified by odor stimulation, suggesting that these oscillations and their interactions with theta oscillations may play roles in olfactory network activity. This could pave the way to further understand the underlying mechanisms of oscillations in olfactory bulb neurons towards odor sensation.