Adaptive regulation of sparseness by feedforward inhibition.
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.
The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, California 92037, USA.
Collins
C
Assisi
Mark
M
Stopfer
Gilles
G
Laurent
Maxim
M
Bazhenov
D000200:Action Potentials / Q000502:physiology; D000222:Adaptation, Physiological; D000704:Analysis of Variance; D000818:Animals; D000845:Annelida; D004305:Dose-Response Relationship, Drug; D008959:Models, Neurological; D024521:Mushroom Bodies / Q000166:cytology; D009415:Nerve Net / Q000502:physiology; D009433:Neural Inhibition / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D017711:Nonlinear Dynamics; D009812:Odorants; D012903:Smell / Q000502:physiology*; D013569:Synapses / Q000502:physiology