TY - JOUR
T1 - Synchronous firing of antennal-lobe projection neurons encodes the behaviorally effective ratio of sex-pheromone components in male Manduca sexta
AU - Martin, Joshua P.
AU - Lei, Hong
AU - Riffell, Jeffrey A.
AU - Hildebrand, John G.
N1 - Funding Information:
Acknowledgments The authors would like to thank E. Constanto-poulos for assistance with behavioral experiments, and A. M. Dacks, C. E. Reisenman, A. Beyerlein, and J. M. Fellous for helpful discussion and comments on this work. This research was supported by the National Institute on Deafness and Other Communication Disorders (NIDCD) grants RO1-DC02751 to JGH and NRSA DC97222 to JPM.
PY - 2013/11
Y1 - 2013/11
N2 - Olfactory stimuli that are essential to an animal's survival and reproduction are often complex mixtures of volatile organic compounds in characteristic proportions. Here, we investigated how these proportions are encoded in the primary olfactory processing center, the antennal lobe, of male Manduca sexta moths. Two key components of the female's sex pheromone, present in an approximately 2:1 ratio, are processed in each of two neighboring glomeruli in the macroglomerular complex (MGC) of males of this species. In wind-tunnel flight experiments, males exhibited behavioral selectivity for ratios approximating the ratio released by conspecific females. The ratio between components was poorly represented, however, in the firing-rate output of uniglomerular MGC projection neurons (PNs). PN firing rate was mostly insensitive to the ratio between components, and individual PNs did not exhibit a preference for a particular ratio. Recording simultaneously from pairs of PNs in the same glomerulus, we found that the natural ratio between components elicited the most synchronous spikes, and altering the proportion of either component decreased the proportion of synchronous spikes. The degree of synchronous firing between PNs in the same glomerulus thus selectively encodes the natural ratio that most effectively evokes the natural behavioral response to pheromone.
AB - Olfactory stimuli that are essential to an animal's survival and reproduction are often complex mixtures of volatile organic compounds in characteristic proportions. Here, we investigated how these proportions are encoded in the primary olfactory processing center, the antennal lobe, of male Manduca sexta moths. Two key components of the female's sex pheromone, present in an approximately 2:1 ratio, are processed in each of two neighboring glomeruli in the macroglomerular complex (MGC) of males of this species. In wind-tunnel flight experiments, males exhibited behavioral selectivity for ratios approximating the ratio released by conspecific females. The ratio between components was poorly represented, however, in the firing-rate output of uniglomerular MGC projection neurons (PNs). PN firing rate was mostly insensitive to the ratio between components, and individual PNs did not exhibit a preference for a particular ratio. Recording simultaneously from pairs of PNs in the same glomerulus, we found that the natural ratio between components elicited the most synchronous spikes, and altering the proportion of either component decreased the proportion of synchronous spikes. The degree of synchronous firing between PNs in the same glomerulus thus selectively encodes the natural ratio that most effectively evokes the natural behavioral response to pheromone.
KW - Glomerulus
KW - Neural coding
KW - Neural synchrony
KW - Olfaction
KW - Pheromone
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U2 - 10.1007/s00359-013-0849-z
DO - 10.1007/s00359-013-0849-z
M3 - Article
C2 - 24002682
AN - SCOPUS:84885950545
SN - 0340-7594
VL - 199
SP - 963
EP - 979
JO - Journal of Comparative Physiology A: Neuroethology, Sensory, Neural, and Behavioral Physiology
JF - Journal of Comparative Physiology A: Neuroethology, Sensory, Neural, and Behavioral Physiology
IS - 11
ER -