Changes in the spectral characteristics and the coherence of the rat olfactory bulb local field potentials under xylazine-tiletamine-zolazepam anesthesia

Abstract

Local field potentials (LFP) recorded in the olfactory bulb (OB) are known to be largely generated in local neural networks, are directly related to the processing of olfactory information, and are influenced by various factors, including anesthetics. Using 8-electrode arrays implanted in the dorsal regions of 6 adult male Norway rats OBs, the effects of xylazine-tiletamine-zolazepam (XTZ) anesthesia on the spectral characteristics and coherence of the LFP in the frequency range 1–150 Hz were studied in 2 hours long chronic experiments. It is shown that the most significant changes in the rat OB LFP under XTZ-anesthesia are observed in the high γ frequency band. A statistically significant increase in the power (2–4 times) and coherence (up to 50%) of this band was observed in the LFP of all animals within 10–15 minutes from the anesthesia onset. At the same time, during wakefulness, the dominant frequencies of this band were 70–80 Hz, and within 10–15 minutes from the anesthesia onset they increased to 110–130 Hz. During anesthesia, a gradual shift of these dominant frequencies to a lower range (90–110 Hz) was observed, while their total power, in contrast to the coherence, was statistically significantly reduced when the animal started recovering from anesthesia