  In recent years, several studies have tended to show a respiratory drive in
numerous brain areas so that the respiratory rhythm could be considered as a
master clock promoting communication between distant brain areas. However,
outside of the olfactory system it is not known if respiration-related
oscillation (RRo) could exist in the membrane potential (MP) of neurons neither
if it can structure spiking discharge. To fill this gap, we co-recorded MP and
LFP activities in different non-olfactory brain areas: median prefrontal cortex
(mPFC), primary somatosensory cortex (S1), primary visual cortex (V1), and
hippocampus (HPC), in urethane-anesthetized rats. Using respiratory cycle by
respiratory cycle analysis, we observed that respiration could modulate both MP
and spiking discharges in all recorded areas. Further quantifications revealed
RRo episodes were transient in most neurons (5 consecutive cycles in average).
RRo development in MP was largely influenced by the presence of respiratory
modulation in the LFP. Finally, moderate hyperpolarization reduced RRo
occurence within cells of mpFC and S1. By showing the respiratory rhythm
influenced brain activity deep to the MP of non-olfactory neurons, our data
support the idea respiratory rhythm could mediate long-range communication.
