title: Sensory memory for odors is encoded in spontaneous correlated activity between olfactory glomeruli.
abstract: Sensory memory is a short-lived persistence of a sensory stimulus in the nervous system, such as iconic memory in the visual system. However, little is known about the mechanisms underlying olfactory sensory memory. We have therefore analyzed the effect of odor stimuli on the first odor-processing network in the honeybee brain, the antennal lobe, which corresponds to the vertebrate olfactory bulb. We stained output neurons with a calcium-sensitive dye and measured across-glomerular patterns of spontaneous activity before and after a stimulus. Such a single-odor presentation changed the relative timing of spontaneous activity across glomeruli in accordance with Hebb's theory of learning. Moreover, during the first few minutes after odor presentation, correlations between the spontaneous activity fluctuations suffice to reconstruct the stimulus. As spontaneous activity is ubiquitous in the brain, modifiable fluctuations could provide an ideal substrate for Hebbian reverberations and sensory memory in other neural systems.
authors.affiliation: Institute for Theoretical Biology, Humboldt-Universität zu Berlin, 10115 Berlin, Germany. galan@cnbc.cmu.edu
authors.forename: Roberto F
authors.initials: RF
authors.lastname: Galán
authors.forename: Marcel
authors.initials: M
authors.lastname: Weidert
authors.forename: Randolf
authors.initials: R
authors.lastname: Menzel
authors.forename: Andreas V M
authors.initials: AV
authors.lastname: Herz
authors.forename: C Giovanni
authors.initials: CG
authors.lastname: Galizia
mesh_terms: D000818:Animals; D001516:Bees / Q000033:anatomy & histology / Q000502:physiology*; D020013:Calcium Signaling / Q000502:physiology; D003712:Dendrites / Q000502:physiology; D005260:Female; D005456:Fluorescent Dyes; D008568:Memory / Q000502:physiology*; D008959:Models, Neurological; D009415:Nerve Net / Q000166:cytology / Q000502:physiology*; D009475:Neurons, Afferent / Q000502:physiology*; D019581:Neuropil / Q000502:physiology; D009812:Odorants; D009830:Olfactory Bulb / Q000166:cytology / Q000502:physiology*; D009833:Olfactory Pathways / Q000166:cytology / Q000502:physiology*; D012903:Smell / Q000502:physiology*; D013569:Synapses / Q000502:physiology; D009435:Synaptic Transmission / Q000502:physiology
chemical_list: D005456:Fluorescent Dyes