Synaptic inhibition in the olfactory bulb accelerates odor discrimination in mice.
Local inhibitory circuits are thought to shape neuronal information processing in the central nervous system, but it remains unclear how specific properties of inhibitory neuronal interactions translate into behavioral performance. In the olfactory bulb, inhibition of mitral/tufted cells via granule cells may contribute to odor discrimination behavior by refining neuronal representations of odors. Here we show that selective deletion of the AMPA receptor subunit GluA2 in granule cells boosted synaptic Ca(2+) influx, increasing inhibition of mitral cells. On a behavioral level, discrimination of similar odor mixtures was accelerated while leaving learning and memory unaffected. In contrast, selective removal of NMDA receptors in granule cells slowed discrimination of similar odors. Our results demonstrate that inhibition of mitral cells controlled by granule cell glutamate receptors results in fast and accurate discrimination of similar odors. Thus, spatiotemporally defined molecular perturbations of olfactory bulb granule cells directly link stimulus similarity, neuronal processing time, and discrimination behavior to synaptic inhibition.
Institute of Anatomy and Cell Biology, University of Heidelberg, INF 307, 69120 Heidelberg, Germany; WIN Olfactory Dynamics Group, Max Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany.
Nixon M
NM
Abraham
Veronica
V
Egger
Derya R
DR
Shimshek
Robert
R
Renden
Izumi
I
Fukunaga
Rolf
R
Sprengel
Peter H
PH
Seeburg
Matthias
M
Klugmann
Troy W
TW
Margrie
Andreas T
AT
Schaefer
Thomas
T
Kuner
D000818:Animals; D001522:Behavior, Animal; D002118:Calcium / Q000378:metabolism; D004193:Discrimination Learning / Q000502:physiology*; D004558:Electric Stimulation / Q000379:methods; D066298:In Vitro Techniques; D053444:Inhibitory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology; D008568:Memory / Q000502:physiology; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009154:Mutation / Q000235:genetics; D009433:Neural Inhibition / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D009812:Odorants; D009830:Olfactory Bulb / Q000166:cytology*; D009833:Olfactory Pathways / Q000502:physiology; D018408:Patch-Clamp Techniques; D018091:Receptors, AMPA / Q000235:genetics; D016194:Receptors, N-Methyl-D-Aspartate / Q000172:deficiency / Q000235:genetics; D012903:Smell / Q000502:physiology; D013569:Synapses / Q000187:drug effects / Q000502:physiology*; D009435:Synaptic Transmission
D018091:Receptors, AMPA; D016194:Receptors, N-Methyl-D-Aspartate; C104722:glutamate receptor ionotropic, AMPA 2; D002118:Calcium