Simultaneous activation of mouse main and accessory olfactory bulbs by odors or pheromones.
It is generally believed that the main olfactory system processes common odors and the accessory olfactory system is specifically for pheromones. The potential for these two systems to respond simultaneously to the same stimuli has not been fully explored due to methodological limitations. Here we examine this phenomenon using high-resolution functional magnetic resonance imaging (fMRI) to reveal simultaneously the responses in the main (MOB) and accessory olfactory bulbs (AOB) to odors and pheromones. Common odorants elicited strong signals in the MOB and weak signals in the AOB. 2-Heptanone, a known mouse pheromone, elicited strong signals in both the MOB and AOB. Urine odor, a complicated mixture of pheromones and odorants, elicited significant signals in limited regions of the MOB and large regions of the AOB. The fMRI results demonstrate that both the main and the accessory olfactory systems may respond to volatile compounds but with different selectivity, suggesting a greater integration of the two olfactory pathways than traditionally believed.
Xu
Fuqiang
F
Department of Diagnostic Radiology, Yale Medical School, New Haven, Connecticut 06520, USA.
Schaefer
Michele
M
Kida
Ikuhiro
I
Schafer
James
J
Liu
Nian
N
Rothman
Douglas L
DL
Hyder
Fahmeed
F
Restrepo
Diego
D
Shepherd
Gordon M
GM
D000818:Animals; D005071:Evoked Potentials / Q000502:physiology; D005260:Female; D007659:Ketones / Q000494:pharmacology; D008279:Magnetic Resonance Imaging; D051379:Mice; D008810:Mice, Inbred C57BL; D009812:Odorants; D009830:Olfactory Bulb / Q000033:anatomy & histology / Q000187:drug effects / Q000502:physiology*; D009833:Olfactory Pathways / Q000187:drug effects / Q000502:physiology; D010675:Pheromones / Q000494:pharmacology*; D010812:Physical Stimulation; D012903:Smell / Q000187:drug effects / Q000502:physiology*; D014556:Urine / Q000737:chemistry
D007659:Ketones; D010675:Pheromones; C011917:2-heptanone