Olfactory coding and spike-timing-dependent plasticity
(December 2, 2003 3:30 PM - 4:30 PM)
Spatial patterns of glomerular activity in the vertebrate olfactory bulb and arthropod antennal lobe are believed to reflect an important component of the first-order olfactory representation and contribute to odorant identification. Higher-concentration odorant stimuli evoke broader glomerular activation patterns, resulting in greater spatial overlap among different odor representations. However, behavioral studies demonstrate results contrary to what these data might suggest: honeybees are more, not less, able to discriminate among odorants when they are applied at higher concentrations. Using a computational model of the honeybee antennal lobe, we here show that changes in synchronization patterns among antennal lobe projection neurons, as observed electrophysiologically in response to odor stimuli of different concentrations, could parsimoniously underlie these behavioral observations. We suggest that "stimulus salience," as defined behaviorally, is directly correlated with the degree of synchronization among second-order olfactory neurons.