Optical imaging of odor-evoked glomerular activity patterns in the antennal lobes of the ant Camponotus rufipes

Ants have a well developed olfactory sense, which they need both for the pe rception of environmental chemicals, and for a highly sophisticated intrasp ecific communication system based on pheromones. The question arises theref ore as Ito how different odors are coded in the antennal lobe, the first ce ntral neuropil to process olfactory information. We measured odor-evoked ac tivity patterns using in vivo neuropil calcium recording in the antennal lo be of the ant Camponotus rufipes. We found that (a) odors elicit focal acti vity spots (diameter ca. 20 mu m) which most probably represent the olfacto ry glomeruli; (b) different odors are coded in odor specific patterns of su ch activated spots, and a particular spot can participate in the pattern fo r different odors; (c) calcium increased in the activated spots within the 2-s stimulation period and slowly declined thereafter.