Antennal lobe spontaneous and stimulus-evoked activity. The video shows 20 s of calcium imaging in the projection neurons of the antennal lobe. While intense activity can be observed during stimulation (green rectangle), ongoing activity can be observed also before and after stimulation. Video was acquired at 25 Hz but presented at 12.5 Hz (every second section was omitted for reduce file size); stimulus (1-octanol 10-2) was delivered two times for 0.1 s, at t = 4 s and t = 14 s. Colormap of raw data presented as ΔR340/380. No filtering or post-processing was applied to this video. Scale bar, 100 μm.