title: Noradrenergic neuromodulation in the olfactory bulb modulates odor habituation and spontaneous discrimination.
abstract: Noradrenergic projections from the locus coeruleus (LC) project to the olfactory bulb (OB), a cortical structure implicated in odor learning and perceptual differentiation among similar odorants. The authors tested the role of OB noradrenaline (NA) in short-term olfactory memory using an animal model of LC degeneration coupled with intrabulbar infusions of NA. Specifically, the authors lesioned cortical noradrenergic fibers in mice with the noradrenergic neurotoxin N-Ethyl-N-(2-chloroethyl)-2-bromobenzylamine hydrochloride (DSP4) and measured the effects on an olfactory habituation/spontaneous discrimination task. DSP4-treated mice failed to habituate to repeated odor presentations, indicating that they could not remember odors over the 5-min intertrial interval. The authors then infused NA bilaterally into the OBs of both DSP4-treated and nonlesioned control animals at two concentrations (10(-3)M and 10(-5)M, 2 microl/side). In DSP4-treated animals, NA administration at either concentration restored normal habituation and spontaneous discrimination performance, indicating that noradrenergic neuromodulation mediates these aspects of perceptual learning and that its efficacy does not require activity-dependent local regulation of NA release. Functional OB learning mechanisms may be necessary for normal odor recognition and differentiation among physically similar odorants.
authors: Laboratoire de Neurosciences Sensorielles, Comportement, Cognition, Université de Lyon, Lyon, France.
authors: Delphine
authors: D
authors: Guérin
authors: Shane T
authors: ST
authors: Peace
authors: Anne
authors: A
authors: Didier
authors: Christiane
authors: C
authors: Linster
authors: Thomas A
authors: TA
authors: Cleland
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D004192:Discrimination, Psychological / Q000187:drug effects / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D005106:Exploratory Behavior / Q000187:drug effects / Q000502:physiology; D006185:Habituation, Psychophysiologic / Q000187:drug effects / Q000502:physiology*; D008297:Male; D051379:Mice; D009638:Norepinephrine / Q000378:metabolism* / Q000494:pharmacology; D009812:Odorants; D009830:Olfactory Bulb / Q000187:drug effects / Q000293:injuries / Q000502:physiology*; D009833:Olfactory Pathways / Q000187:drug effects / Q000502:physiology; D012717:Sesquiterpenes / Q000494:pharmacology; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism
chemical_list: D012717:Sesquiterpenes; C018119:odoratin; D014446:Tyrosine 3-Monooxygenase; D009638:Norepinephrine