title: Functional organization of sensory input to the olfactory bulb glomerulus analyzed by two-photon calcium imaging.
abstract: Glomeruli in the olfactory bulb are anatomically discrete modules receiving input from idiotypic olfactory sensory neurons. To examine the functional organization of sensory inputs to individual glomeruli, we loaded olfactory sensory neurons with a Ca(2+) indicator and measured odorant-evoked presynaptic Ca(2+) signals within single glomeruli by using two-photon microscopy in anaesthetized mice. Odorants evoked patterns of discrete Ca(2+) signals throughout the neuropil of a glomerulus. Across glomeruli, Ca(2+) signals occurred with equal probability in all glomerular regions. Within single glomeruli, the pattern of intraglomerular Ca(2+) signals was indistinguishable for stimuli of different duration, identity, and concentration. Moreover, the response time course of the signals was similar throughout the glomerulus. Hence, sensory inputs to individual glomeruli are spatially heterogeneous but seem to be functionally indiscriminate. These results support the view of olfactory glomeruli as functional units in representing sensory information.
authors.affiliation: Department of Biology, Boston University, 5 Cummington Street, Boston, MA 02215, USA.
authors.forename: Matt
authors.initials: M
authors.lastname: Wachowiak
authors.forename: Winfried
authors.initials: W
authors.lastname: Denk
authors.forename: Rainer W
authors.initials: RW
authors.lastname: Friedrich
mesh_terms: D000818:Animals; D002118:Calcium / Q000032:analysis; D020013:Calcium Signaling / Q000502:physiology*; D007091:Image Processing, Computer-Assisted; D051379:Mice; D008856:Microscopy, Fluorescence / Q000379:methods*; D009830:Olfactory Bulb / Q000166:cytology / Q000502:physiology*; D018034:Olfactory Receptor Neurons / Q000502:physiology*; D017785:Photons; D012903:Smell / Q000502:physiology*; D013268:Stimulation, Chemical; D013569:Synapses / Q000502:physiology
chemical_list: D002118:Calcium