FIGURE 6.

Odor and post-odor responses evolve differently in different brain areas. (A) Correlation analyses of repeated odorant stimulations (trial 1 vs. trial 2) show that odor and post-odor response patterns are reproducible and stable in PN somata, KC dendrites, and KC somata (see high correlation values during the odor and after odor offset). In PN somata, the odor response pattern changes into a distinct post-odor response at odor offset (see the gray areas right and below the correlated odor pattern rectangles). In KC dendrites, and even more in KC somata, the pattern change is smooth and the post-odor response pattern retains a similarity to the odor response pattern. Correlation values were defined as being significant when p < 0.005 and are color coded (color scale bar, right). Non-significant values are shown in gray. Purple and blue frames mark the time windows used to calculate the time-resolved correlation, shown in (B). (B) Time-resolved correlation between the odor response pattern (marked by the purple square above the graph) and the post-odor response pattern (marked by the blue square) of an odor response with all time points of another response to the same odorant (purple and blue traces, respectively). The odor response pattern breaks down at odor offset in PN somata, and yields to a distinct post-odor response pattern which evolves at odor offset. Conversely, KC somata show a smooth transition that retains substantial information about the odorant response also during post-odor activity. Mean ± SD obtained by bootstrap analysis (on animals, 1000 times). See Supplementary Figure S3 for the same data split by odorants. (C) Correlation of the odor response patterns of different odorants and repeated odorant stimulations. Each odorant was given twice (e.g., ButL 1 and ButL 2; see methods for odorant abbreviations). Odor response patterns of repeated odorants are reproducible in all three cell/compartment types (large diagonal squares in the upper row). Some odorants elicited similar response patterns in KC dendrites (off-diagonal dark squares, e.g., ButL 1 and ButL 2 with ProL 1 and ProL 2). (D) Correlation of the post-odor response patterns between different odorants. Post-odor patterns are not reproducible in PN somata (high values along the diagonal form only small squares), but quite reproducible in KC dendrites and KC somata (large squares in the diagonal with high correlation values). (E) Correlation of odor response patterns with post-odor response patterns. In PN somata or KC dendrites, the odor response patterns are not correlated to the post-odor response patterns within the same odorant stimulation (see diagonal entries), but there is a consistent correlation in KC somata (increase in correlation along the diagonal). See Materials and Methods for number of flies and somata/ROIs.