title: The relationship between respiration-related membrane potential slow oscillations and discharge patterns in mitral/tufted cells: what are the rules?
abstract: BACKGROUND
  A slow respiration-related rhythm strongly shapes the activity of the olfactory bulb. This rhythm appears as a slow oscillation that is detectable in the membrane potential, the respiration-related spike discharge of the mitral/tufted cells and the bulbar local field potential. Here, we investigated the rules that govern the manifestation of membrane potential slow oscillations (MPSOs) and respiration-related discharge activities under various afferent input conditions and cellular excitability states.
  
  
  RESULTS
  We recorded the intracellular membrane potential signals in the mitral/tufted cells of freely breathing anesthetized rats. We first demonstrated the existence of multiple types of MPSOs, which were influenced by odor stimulation and discharge activity patterns. Complementary studies using changes in the intracellular excitability state and a computational model of the mitral cell demonstrated that slow oscillations in the mitral/tufted cell membrane potential were also modulated by the intracellular excitability state, whereas the respiration-related spike activity primarily reflected the afferent input. Based on our data regarding MPSOs and spike patterns, we found that cells exhibiting an unsynchronized discharge pattern never exhibited an MPSO. In contrast, cells with a respiration-synchronized discharge pattern always exhibited an MPSO. In addition, we demonstrated that the association between spike patterns and MPSO types appeared complex.
  
  
  CONCLUSIONS
  We propose that both the intracellular excitability state and input strength underlie specific MPSOs, which, in turn, constrain the types of spike patterns exhibited.
authors.affiliation: Lyon Neuroscience Research Center, Team Olfaction: From Coding to Memory, Centre National de Recherche Scientifique (CNRS) Unité Mixte de Recherche 5292 - Institut National de Santé Et de Recherche Médicale (INSERM) U1028 - Université Lyon 1, Lyon, France. vbriffaud@olfac.univ-lyon1.fr
authors.forename: Virginie
authors.initials: V
authors.lastname: Briffaud
authors.forename: Nicolas
authors.initials: N
authors.lastname: Fourcaud-Trocmé
authors.forename: Belkacem
authors.initials: B
authors.lastname: Messaoudi
authors.forename: Nathalie
authors.initials: N
authors.lastname: Buonviso
authors.forename: Corine
authors.initials: C
authors.lastname: Amat
mesh_terms: D000818:Animals; D042541:Intracellular Space / Q000378:metabolism; D007700:Kinetics; D008297:Male; D008564:Membrane Potentials; D009812:Odorants; D009830:Olfactory Bulb / Q000166:cytology* / Q000502:physiology*; D010507:Periodicity; D051381:Rats; D017208:Rats, Wistar; D012119:Respiration