@article {48312, title = {Neural coding of perceived odor intensity.}, journal = {eNeuro}, volume = {2}, year = {2015}, month = {2015 Nov-Dec}, abstract = {

Stimulus intensity is a fundamental perceptual feature in all sensory systems. In olfaction, perceived odor intensity depends on at least two variables: odor concentration; and duration of the odor exposure or adaptation. To examine how neural activity at early stages of the olfactory system represents features relevant to intensity perception, we studied the responses of mitral/tufted cells (MTCs) while manipulating odor concentration and exposure duration. Temporal profiles of MTC responses to odors changed both as a function of concentration and with adaptation. However, despite the complexity of these responses, adaptation and concentration dependencies behaved similarly. These similarities were visualized by principal component analysis of average population responses and were quantified by discriminant analysis in a trial-by-trial manner. The qualitative functional dependencies of neuronal responses paralleled psychophysics results in humans. We suggest that temporal patterns of MTC responses in the olfactory bulb contribute to an internal perceptual variable: odor intensity.

}, keywords = {Adaptation, Physiological, Animals, Mice, Inbred C57BL, Neurons, Odorants, Olfactory Bulb, Perception, Smell}, issn = {2373-2822}, doi = {10.1523/ENEURO.0083-15.2015}, author = {Sirotin, Yevgeniy B and Shusterman, Roman and Rinberg, Dmitry} } @article {4148, title = {Perception of sniff phase in mouse olfaction.}, journal = {Nature}, volume = {14}, year = {2011}, month = {2011 Oct 12}, pages = {1039-44}, abstract = {

Olfactory systems encode odours by which neurons respond and by when they respond. In mammals, every sniff evokes a precise, odour-specific sequence of activity across olfactory neurons. Likewise, in a variety of neural systems, ranging from sensory periphery to cognitive centres, neuronal activity is timed relative to sampling behaviour and/or internally generated oscillations. As in these neural systems, relative timing of activity may represent information in the olfactory system. However, there is no evidence that mammalian olfactory systems read such cues. To test whether mice perceive the timing of olfactory activation relative to the sniff cycle ({\textquoteright}sniff phase{\textquoteright}), we used optogenetics in gene-targeted mice to generate spatially constant, temporally controllable olfactory input. Here we show that mice can behaviourally report the sniff phase of optogenetically driven activation of olfactory sensory neurons. Furthermore, mice can discriminate between light-evoked inputs that are shifted in the sniff cycle by as little as 10 milliseconds, which is similar to the temporal precision of olfactory bulb odour responses. Electrophysiological recordings in the olfactory bulb of awake mice show that individual cells encode the timing of photoactivation in relation to the sniff in both the timing and the amplitude of their responses. Our work provides evidence that the mammalian olfactory system can read temporal patterns, and suggests that timing of activity relative to sampling behaviour is a potent cue that may enable accurate olfactory percepts to form quickly.

}, issn = {1476-4687}, doi = {10.1038/nature10521}, author = {Smear, Matthew and Shusterman, Roman and O{\textquoteright}Connor, Rodney and Bozza, Thomas and Rinberg, Dmitry} } @article {3421, title = {Precise olfactory responses tile the sniff cycle.}, journal = {Nature Neuroscience}, volume = {14}, year = {2011}, month = {2011 Jul 17}, pages = {1039-44}, abstract = {

In terrestrial vertebrates, sniffing controls odorant access to receptors, and therefore sets the timescale of olfactory stimuli. We found that odorants evoked precisely sniff-locked activity in mitral/tufted cells in the olfactory bulb of awake mouse. The trial-to-trial response jitter averaged 12 ms, a precision comparable to other sensory systems. Individual cells expressed odor-specific temporal patterns of activity and, across the population, onset times tiled the duration of the sniff cycle. Responses were more tightly time-locked to the sniff phase than to the time after inhalation onset. The spikes of single neurons carried sufficient information to discriminate odors. In addition, precise locking to sniff phase may facilitate ensemble coding by making synchrony relationships across neurons robust to variation in sniff rate. The temporal specificity of mitral/tufted cell output provides a potentially rich source of information for downstream olfactory areas.

}, issn = {1546-1726}, doi = {10.1038/nn.2877}, author = {Shusterman, Roman and Smear, Matthew C and Koulakov, Alexei A and Rinberg, Dmitry} }