Identification and characterization of an output neuron from the oscillatory molluscan olfactory network.
Synchronous oscillations in olfactory systems have been thought to play critical roles in encoding olfactory information. However, their role in determining behavior is unknown. As a first step toward understanding the decoding process of coherent oscillation, we looked for a neuron in the terrestrial slug Limax marginatus that receives output signals from the procerebrum (PC), which is the olfactory center of Limax. We identified a neuron in the metacerebrum that extends its neurites into both the PC and the metacerebrum, and named it the metacerebro-procerebral neuron (MPN). The MPN exhibited a membrane potential oscillation that was synchronous with the local field potential oscillation in the PC. When we cut the PC off, the membrane potential oscillation of the MPN disappeared. Numerous varicosities were found on the neurites in the metacerebrum, while no varicosities were found on the neurites inside the PC. From these morphological and physiological results, we conclude that the MPN is an output neuron from the PC. The MPN also receives monosynaptic inputs from the superior and inferior tentacle nerves. The MPN thus may receive olfactory information from two pathways, one directly from the sensory organ and the other by way of the PC, possibly functioning to integrate them.
Shimozono
S
S
Laboratory of Neurobiophysics, School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
Watanabe
S
S
Inoue
T
T
Kirino
Y
Y
D000818:Animals; D001683:Biological Clocks / Q000502:physiology*; D002232:Carbocyanines; D002490:Central Nervous System / Q000166:cytology* / Q000187:drug effects / Q000502:physiology; D004558:Electric Stimulation; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology; D005456:Fluorescent Dyes; D017952:Ganglia, Invertebrate / Q000166:cytology* / Q000187:drug effects / Q000502:physiology; D018698:Glutamic Acid / Q000494:pharmacology; D008239:Lysine / Q000031:analogs & derivatives*; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D008974:Mollusca / Q000166:cytology* / Q000502:physiology; D016501:Neurites / Q000502:physiology / Q000648:ultrastructure; D009474:Neurons / Q000166:cytology* / Q000187:drug effects / Q000502:physiology; D009833:Olfactory Pathways / Q000166:cytology* / Q000187:drug effects / Q000502:physiology; D017729:Presynaptic Terminals / Q000502:physiology / Q000648:ultrastructure; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology; D012903:Smell / Q000187:drug effects / Q000502:physiology; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology
C035005:3,3'-dihexadecylindocarbocyanine; D002232:Carbocyanines; D005456:Fluorescent Dyes; D018698:Glutamic Acid; C013411:biocytin; D008239:Lysine