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Free keywords:
Action Potentials/physiology
*Adaptation, Physiological
Analysis of Variance
Animals
Annelida
Dose-Response Relationship, Drug
*Models, Neurological
Mushroom Bodies/cytology
Nerve Net/physiology
Neural Inhibition/*physiology
Neurons/*physiology
Nonlinear Dynamics
*Odorants
Smell/*physiology
Synapses/physiology
Abstract:
In the mushroom body of insects, odors are represented by very few spikes in a small number of neurons, a highly efficient strategy known as sparse coding. Physiological studies of these neurons have shown that sparseness is maintained across thousand-fold changes in odor concentration. Using a realistic computational model, we propose that sparseness in the olfactory system is regulated by adaptive feedforward inhibition. When odor concentration changes, feedforward inhibition modulates the duration of the temporal window over which the mushroom body neurons may integrate excitatory presynaptic input. This simple adaptive mechanism could maintain the sparseness of sensory representations across wide ranges of stimulus conditions.
