RT Journal Article
SR Electronic
T1 Sniff-invariant intensity perception using olfactory bulb coding of inhalation dynamics
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 226969
DO 10.1101/226969
A1 Rebecca Jordan
A1 Mihaly Kollo
A1 Andreas T Schaefer
YR 2017
UL http://biorxiv.org/content/early/2017/12/06/226969.abstract
AB For stable perception of odor intensity, there must exist a neural correlate that is invariant across other parameters, such as the highly variable sniff cycle. Previous hypotheses suggest that variance in inhalation dynamics alters odor concentration profiles in the naris despite a constant environmental concentration. Using whole cell recordings in the olfactory bulb of awake mice, we directly demonstrate that rapid sniffing mimics the effect of odor concentration increase at the level of both mitral and tufted cell (MTC) firing rate responses and temporal responses. In contrast, we find that mice are capable of discriminating concentrations within short timescales despite highly variable sniffing behavior. We reason that the only way the olfactory system can differentiate between a change in sniffing and a change in concentration is to receive information about the inhalation parameters in parallel with information about the odor. While conceivably this could be achieved via corollary discharge from respiration control centres, we find that the sniff-driven activity of MTCs without odor input is informative of the kind of inhalation that just occurred, allowing rapid detection of a change in inhalation. Thus, a possible reason for sniff modulation of the early olfactory system may be to inform downstream centres of nasal flow dynamics, so that an inference can be made about environmental concentration independent of sniff variance.