title: Classification of odorants across layers in locust olfactory pathway.
abstract: Olfactory processing takes place across multiple layers of neurons from the transduction of odorants in the periphery, to odor quality processing, learning, and decision making in higher olfactory structures. In insects, projection neurons (PNs) in the antennal lobe send odor information to the Kenyon cells (KCs) of the mushroom bodies and lateral horn neurons (LHNs). To examine the odor information content in different structures of the insect brain, antennal lobe, mushroom bodies and lateral horn, we designed a model of the olfactory network based on electrophysiological recordings made in vivo in the locust. We found that populations of all types (PNs, LHNs, and KCs) had lower odor classification error rates than individual cells of any given type. This improvement was quantitatively different from that observed using uniform populations of identical neurons compared with spatially structured population of neurons tuned to different odor features. This result, therefore, reflects an emergent network property. Odor classification improved with increasing stimulus duration: for similar odorants, KC and LHN ensembles reached optimal discrimination within the first 300-500 ms of the odor response. Performance improvement with time was much greater for a population of cells than for individual neurons. We conclude that, for PNs, LHNs, and KCs, ensemble responses are always much more informative than single-cell responses, despite the accumulation of noise along with odor information.
authors: Department of Medicine, University of California, San Diego, California;
authors: Pavel
authors: P
authors: Sanda
authors: Department of Medicine, University of California, San Diego, California; Department of Cell Biology and Neuroscience, University of California, Riverside, California;
authors: Tiffany
authors: T
authors: Kee
authors: National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland; and Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur, India.
authors: Nitin
authors: N
authors: Gupta
authors: National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland; and.
authors: Mark
authors: M
authors: Stopfer
authors: Department of Medicine, University of California, San Diego, California; bazhenov@salk.edu.
authors: Maxim
authors: M
authors: Bazhenov
mesh_terms: D000818:Animals; D004192:Discrimination, Psychological; D006110:Grasshoppers; D024521:Mushroom Bodies / Q000166:cytology / Q000502:physiology; D009812:Odorants; D009833:Olfactory Pathways / Q000166:cytology / Q000502:physiology*; D055696:Olfactory Perception; D011984:Sensory Receptor Cells / Q000502:physiology*
keywords: locust olfaction; network model; odor concentration; odor discrimination