Figure 2
From: Sparsened neuronal activity in an optogenetically activated olfactory glomerulus
Neuropil signals in the 7250 target glomerulus during ethyl tiglate and laser stimulation (stimulus intensities as indicated). (A) Frame subtractions (left) and fluorescence intensity vs. time traces (right) showing odor vs. laser-evoked neuronal activity. Glomeruli are indicated with dashed lines; the target glomerulus is green. Grey bars in the right panels of (A) indicate the frames that were used to create the frame subtractions. The scale bar on the left applies to top and bottom panels. (B) The number of glomeruli that respond to odor vs. laser stimuli; responses were recorded in imaging frames sized 205–335 μm2. (C) Average calcium signals from multiple target glomeruli. The signals were normalized by dividing traces from ethyl tiglate and laser stimulation trials by the mean fluorescence intensity during the evoked response at 4.6–9.2 sec. Dashed lines indicate standard deviations. (D) Histogram comparing signal amplitudes in the neuropil; data were averaged and normalized as in (C). (E) Neuropil calcium signals that were normalized by setting the maximum of each trace to 1.0 to reveal the signal shapes (no temporal smoothing). The laser-evoked response has a slightly shorter latency than the odor-evoked response onset (arrow). (F) Histogram showing correlations of odor and laser-evoked calcium signals to the shape of the square command pulse for each stimulus (determined by measuring the Euclidian distance between the stimulus command pulse and the calcium signals). The black line in (A,C,E) indicates the duration of the stimulus command pulse. The abbreviation ET denotes the odor ethyl tiglate.
