Figure 2

Local dendritic directional preferences of various lobula plate tangential cells (LPTCs). Calcium signals at the dendrites of three different LPTC classes: vertical system (VS)3 cells (a), neurons called Amacrine cell (b) and ventral centrifugal horizontal cells (c). (i) Local differences in fluorescence intensity recorded in a single cell during pattern motion in eight directions (α) in comparison to an average of the last three frames before onset of motion. Signals were averaged over the last 500 ms of stimulus motion. (ii) Integrated local calcium responses to pattern motion in eight directions - the same cell as in (i). The grid of region of interest (ROIs) is indicated in the upper left corner. White arrows show increases in calcium in the underlying ROI in response to motion in the direction of the arrow; red arrows show decreases. Arrow length (normalized to the arrow with maximum amplitude in the image) represents ΔF/F intensity. (iii): Resulting response vectors from vector summation of the individual response vectors to all stimulus directions (normalized as before) - the same cell as in (i). Arrow brightness represents overall response amplitude. (iv) Resulting response vectors of additional cells of each of the cell types recorded in different flies, calculated as in (iii). In (c), right column, the profile faintly visible in the dorsal area is a VS cell which was accidentally stained during tissue penetration. The cell did not noticeably contribute to the calcium signals. Images represent single recording traces and were taken at 10 Hz and 512 × 512 px resolution.