Fig. 3.

Odors evoke specific patterns of glomerular activity in the Drosophila antennal lobe. The calcium-sensitive protein G-CaMP has been genetically expressed in either projection neurons (above) or sensory neurons (below). Calcium signals to two different odors have been superimposed onto the morphological image of the antennal lobe. Both odors lead to a specific, but different pattern of activated glomeruli. The activities are bilaterally symmetric between the left and the right antennal lobe. Comparison of the activity patterns between the sensory and the projection neurons to the same odor reveals similar but not identical responses