title: Cortical Feedback Decorrelates Olfactory Bulb Output in Awake Mice.
abstract: The olfactory bulb receives rich glutamatergic projections from the piriform cortex. However, the dynamics and importance of these feedback signals remain unknown. Here, we use multiphoton calcium imaging to monitor cortical feedback in the olfactory bulb of awake mice and further probe its impact on the bulb output. Responses of feedback boutons were sparse, odor specific, and often outlasted stimuli by several seconds. Odor presentation either enhanced or suppressed the activity of boutons. However, any given bouton responded with stereotypic polarity across multiple odors, preferring either enhancement or suppression. Feedback representations were locally diverse and differed in dynamics across bulb layers. Inactivation of piriform cortex increased odor responsiveness and pairwise similarity of mitral cells but had little impact on tufted cells. We propose that cortical feedback differentially impacts these two output channels of the bulb by specifically decorrelating mitral cell responses to enable odor separation.
authors.affiliation: Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA.
authors.forename: Gonzalo H
authors.initials: GH
authors.lastname: Otazu
authors.affiliation: Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA.
authors.forename: Honggoo
authors.initials: H
authors.lastname: Chae
authors.affiliation: Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA.
authors.forename: Martin B
authors.initials: MB
authors.lastname: Davis
authors.affiliation: Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA; Watson School of Biological Sciences, Cold Spring Harbor, NY 11724, USA. Electronic address: albeanu@cshl.edu.
authors.forename: Dinu F
authors.initials: DF
authors.lastname: Albeanu
mesh_terms: D000080:Acetals / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002540:Cerebral Cortex / Q000502:physiology*; D005106:Exploratory Behavior / Q000187:drug effects / Q000502:physiology; D056228:Feedback, Sensory / Q000187:drug effects / Q000502:physiology*; D058785:GABA-A Receptor Agonists / Q000494:pharmacology; D008164:Luminescent Proteins / Q000235:genetics; D051379:Mice; D008822:Mice, Transgenic; D009118:Muscimol / Q000494:pharmacology; D009812:Odorants; D009830:Olfactory Bulb / Q000166:cytology / Q000502:physiology*; D009833:Olfactory Pathways / Q000187:drug effects / Q000502:physiology*; D016704:Synapsins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D013997:Time Factors; D014851:Wakefulness / Q000502:physiology*
chemical_list: D000080:Acetals; D058785:GABA-A Receptor Agonists; D008164:Luminescent Proteins; D016704:Synapsins; D009118:Muscimol; D002118:Calcium