Neural processing at the speed of smell.

Olfaction is typically described as behaviorally slow, suggesting neural processes on the order of hundreds of milliseconds to seconds as candidate mechanisms in the creation of olfactory percepts. Whereas a recent study challenged this view in suggesting that a single sniff was sufficient for optimal olfactory discrimination, a study by Abraham et al. in this issue of Neuron sets out to negate the challenge by demonstrating increased processing time for discrimination of similar versus dissimilar stimuli. Here we reconcile both studies, which in our view together support the notion of a speed-accuracy tradeoff in olfactory discriminations that are made within about 200 ms. These findings are discussed in light of the challenges related to defining olfactory perceptual similarity in nonhuman animals.