Activity-dependent plasticity in an olfactory circuit.
Olfactory sensory neurons (OSNs) form synapses with local interneurons and second-order projection neurons to form stereotyped olfactory glomeruli. This primary olfactory circuit is hard-wired through the action of genetic cues. We asked whether individual glomeruli have the capacity for stimulus-evoked plasticity by focusing on the carbon dioxide (CO2) circuit in Drosophila. Specialized OSNs detect this gas and relay the information to a dedicated circuit in the brain. Prolonged exposure to CO2 induced a reversible volume increase in the CO2-specific glomerulus. OSNs showed neither altered morphology nor function after chronic exposure, but one class of inhibitory local interneurons showed significantly increased responses to CO2. Two-photon imaging of the axon terminals of a single PN innervating the CO2 glomerulus showed significantly decreased functional output following CO2 exposure. Behavioral responses to CO2 were also reduced after such exposure. We suggest that activity-dependent functional plasticity may be a general feature of the Drosophila olfactory system.
Sachse
Silke
S
Laboratory of Neurogenetics and Behavior, The Rockefeller University, 1230 York Avenue, Box 63, New York, NY 10065, USA.
Rueckert
Erroll
E
Keller
Andreas
A
Okada
Ryuichi
R
Tanaka
Nobuaki K
NK
Ito
Kei
K
Vosshall
Leslie B
LB
D015502:Absorptiometry, Photon; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D001921:Brain / Q000033:anatomy & histology / Q000502:physiology; D002245:Carbon Dioxide / Q000378:metabolism / Q000494:pharmacology; D004330:Drosophila; D005260:Female; D005455:Fluorescent Antibody Technique; D007395:Interneurons / Q000187:drug effects / Q000502:physiology; D009473:Neuronal Plasticity / Q000187:drug effects / Q000502:physiology*; D009475:Neurons, Afferent / Q000502:physiology; D009812:Odorants; D009833:Olfactory Pathways / Q000033:anatomy & histology / Q000187:drug effects / Q000502:physiology*; D012903:Smell / Q000187:drug effects / Q000502:physiology*
D002245:Carbon Dioxide