title: Sensory-Evoked Intrinsic Imaging Signals in the Olfactory Bulb Are Independent of Neurovascular Coupling.
abstract: Functional brain-imaging techniques used in humans and animals, such as functional MRI and intrinsic optical signal (IOS) imaging, are thought to largely rely on neurovascular coupling and hemodynamic responses. Here, taking advantage of the well-described micro-architecture of the mouse olfactory bulb, we dissected the nature of odor-evoked IOSs. Using in vivo pharmacology in transgenic mouse lines reporting activity in different cell types, we show that parenchymal IOSs are largely independent of neurotransmitter release and neurovascular coupling. Furthermore, our results suggest that odor-evoked parenchymal IOSs originate from changes in light scattering of olfactory sensory neuron axons, mostly due to water movement following action potential propagation. Our study sheds light on a direct correlate of neuronal activity, which may be used for large-scale functional brain imaging.
authors.affiliation: Department of Basic Neurosciences, School of Medicine, University of Geneva, 1211 Geneva, Switzerland; Geneva Neuroscience Center, University of Geneva, 1211 Geneva, Switzerland.
authors.forename: Roberto
authors.initials: R
authors.lastname: Vincis
authors.affiliation: Department of Basic Neurosciences, School of Medicine, University of Geneva, 1211 Geneva, Switzerland; Geneva Neuroscience Center, University of Geneva, 1211 Geneva, Switzerland.
authors.forename: Samuel
authors.initials: S
authors.lastname: Lagier
authors.affiliation: Geneva Neuroscience Center, University of Geneva, 1211 Geneva, Switzerland; Department of Radiology and Medical Informatics, University of Geneva, 1211 Geneva, Switzerland; Institute of Bioengineering, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland.
authors.forename: Dimitri
authors.initials: D
authors.lastname: Van De Ville
authors.affiliation: Geneva Neuroscience Center, University of Geneva, 1211 Geneva, Switzerland; Department of Genetics and Evolution, University of Geneva, 1211 Geneva, Switzerland. Electronic address: ivan.rodriguez@unige.ch.
authors.forename: Ivan
authors.initials: I
authors.lastname: Rodriguez
authors.affiliation: Department of Basic Neurosciences, School of Medicine, University of Geneva, 1211 Geneva, Switzerland; Geneva Neuroscience Center, University of Geneva, 1211 Geneva, Switzerland. Electronic address: alan.carleton@unige.ch.
authors.forename: Alan
authors.initials: A
authors.lastname: Carleton
mesh_terms: D000818:Animals; D001369:Axons / Q000378:metabolism; D000067493:Dynamic Light Scattering; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D005260:Female; D006439:Hemodynamics; D008279:Magnetic Resonance Imaging; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D008856:Microscopy, Fluorescence; D018377:Neurotransmitter Agents / Q000378:metabolism; D000069336:Neurovascular Coupling / Q000502:physiology*; D009830:Olfactory Bulb / Q000502:physiology*; D051842:Olfactory Marker Protein / Q000235:genetics / Q000378:metabolism; D018034:Olfactory Receptor Neurons / Q000378:metabolism; D009994:Osmolar Concentration
chemical_list: D018377:Neurotransmitter Agents; D051842:Olfactory Marker Protein; C497598:Omp protein, mouse