title: Brainstem-mediated sniffing and respiratory modulation during odor stimulation.
abstract: The trigeminal and olfactory systems interact during sensory processing of odor. Here, we investigate odor-evoked modulations of brainstem respiratory networks in a decerebrated perfused brainstem preparation of rat with intact olfactory bulbs. Intranasal application of non-trigeminal odors (rose) did not evoke respiratory modulation in absence of cortico-limbic circuits. Conversely, trigeminal odors such as menthol or lavender evoked robust respiratory modulations via direct activation of preserved brainstem circuits. Trigeminal odors consistently triggered short phrenic nerve bursts (fictive sniff), and the strong trigeminal odor menthol also triggered a slowing of phrenic nerve frequency. Phrenic and vagal nerve recordings reveal that fictive sniffs transiently interrupted odor evoked tonic postinspiratory vagal discharge. This motor pattern is significantly different from normal (eupneic) respiratory activity. In conclusion, we show for the first time the direct involvement of brainstem circuits in primary odor processing to evoke protective sniffs and respiratory modulation in the complete absence of forebrain commands.
authors.affiliation: Zoological Institute, University of Regensburg, D-93040 Regensburg, Germany. Electronic address: Fernando.Perez@biologie.uni-regensburg.de.
authors.forename: Fernando
authors.initials: F
authors.lastname: Pérez de Los Cobos Pallares
authors.affiliation: Florey Institute of Neuroscience and Mental Health, University of Melbourne, Gate 11 Royal Parade, Victoria 3052, Australia.
authors.forename: Tara G
authors.initials: TG
authors.lastname: Bautista
authors.affiliation: Florey Institute of Neuroscience and Mental Health, University of Melbourne, Gate 11 Royal Parade, Victoria 3052, Australia.
authors.forename: Davor
authors.initials: D
authors.lastname: Stanić
authors.affiliation: Zoological Institute, University of Regensburg, D-93040 Regensburg, Germany.
authors.forename: Veronica
authors.initials: V
authors.lastname: Egger
authors.affiliation: Florey Institute of Neuroscience and Mental Health, University of Melbourne, Gate 11 Royal Parade, Victoria 3052, Australia. Electronic address: mathias.dutschmann@florey.edu.au.
authors.forename: Mathias
authors.initials: M
authors.lastname: Dutschmann
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001933:Brain Stem / Q000502:physiology*; D004558:Electric Stimulation; D005071:Evoked Potentials / Q000502:physiology; D009046:Motor Neurons / Q000502:physiology; D009812:Odorants; D009830:Olfactory Bulb / Q000502:physiology*; D010791:Phrenic Nerve / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012119:Respiration; D014276:Trigeminal Nerve / Q000502:physiology
keywords: Behavior; Brainstem; Trigeminal