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Free keywords:
Action Potentials/*physiology
Animals
Grasshoppers/cytology/*physiology
Learning/*physiology
Mushroom Bodies/cytology/*metabolism
Neuronal Plasticity/*physiology
Odorants/analysis
Smell/*physiology
Synapses/metabolism
Synaptic Transmission
Time Factors
Abstract:
Odour representations in insects undergo progressive transformations and decorrelation from the receptor array to the presumed site of odour learning, the mushroom body. There, odours are represented by sparse assemblies of Kenyon cells in a large population. Using intracellular recordings in vivo, we examined transmission and plasticity at the synapse made by Kenyon cells onto downstream targets in locusts. We find that these individual synapses are excitatory and undergo hebbian spike-timing dependent plasticity (STDP) on a +/-25 ms timescale. When placed in the context of odour-evoked Kenyon cell activity (a 20-Hz oscillatory population discharge), this form of STDP enhances the synchronization of the Kenyon cells' targets and thus helps preserve the propagation of the odour-specific codes through the olfactory system.
