Reshaping of Bulbar Odor Response by Nasal Flow Rate in the Rat

The impact of respiratory dynamics on odor response has been poorly studied at the olfactory bulb level. However, it has been shown that sniffing in the behaving rodent is highly dynamic and varies both in frequency and flow rate. Bulbar odor response could vary with these sniffing parameter variations. Consequently, it is necessary to understand how nasal airflow can modify and shape odor response at the olfactory bulb level.To assess this question, we used a double cannulation and simulated nasal airflow protocol on anesthetized rats to uncouple nasal airflow from animal respiration. Both mitral/tufted cell extracellular unit activity and local field potentials (LFPs) were recorded. We found that airflow changes in the normal range were sufficient to substantially reorganize the response of the olfactory bulb. In particular, cellular odor-evoked activities, LFP oscillations and spike phase-locking to LFPs were strongly modified by nasal flow rate.Our results indicate the importance of reconsidering the notion of odor coding as odor response at the bulbar level is ceaselessly modified by respiratory dynamics

Modeling intracellular silent oscillations and rhythmic discharge in olfactory bulb mitral cells

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MOOC Les neurosciences dans ma pratique professionnelle

Module d'autoformationModule d'autoformation destiné à tout professionnels de l'orientation, de la formation, de l'insertion et de l'emploi de la région Auvergne-Rhône-Alpes, pour comprendre la façon dont le cerveau humain apprend, adapter sa pratique professionnelle en tenant compte des apports des neurosciences, et repenser l’apprentissag

In vivo beta and gamma subthreshold oscillations in rat mitral cells: origin and gating by respiratory dynamics

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Respiratory influence on brain dynamics: the preponderant role of the nasal pathway and deep slow regime

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Respiration-gated formation of gamma and beta neural assemblies in the mammalian olfactory bulb

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Respiratory rhythm entrains membrane potential and spiking of non-olfactory neurons

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