Dartboards

Explanation

This method was described earlier in Diercks et al. (2019). It aims to assign detected Calcium Microdomains to areas on a dartboard. It provides an easy-to-understand overview of the distribution of signals and allows to compare whole sets of cells with each other.

How it works

In order to assign the detected signals to certain dartboard areas, the (1) relative distance of the signal from the centroid coordinates (of the frame) and (2) the angle relative to the centroid coordinates are measured. This enables to project each signal onto a normalized dartboard. Signals close to the edge are projected to an outer area on the dartbaord, for example. Preservation of the signal distribution requires the normalization of the signal information to the bead contact position. We chose the position “2 o’clock” as the normalized bead contact position. If a cell has the bead contact at 10 o’clock, for example, then all the signal information will be normalized to the contact site, so that superposition of multiple information from different cells and frames leads to a correct dartboard representation.

Illustration

24 cells have been processed with our pipeline. For each cell and frame, there is a dartboard representation that is normalized to the specific bead contact site of the cell. All the dartboard information for the frames within the first 5 seconds after bead contact were cumulated and divided by 5 to obtain the mean number and distribution of signals within the first 5 seconds.

Representation and usage

After running the script, you can find Excel-files for each cell saved on your computer.

The Excel files contain information for each frame and each dartboard area, leading to a 2D-Matrix/table. There are 37 dartboard areas. The bullseye in the middle is 12.5 times larger than all the other dartbaord areas, which are equal in size. Outside of the bullseye, there are three rings - each consisting of 12 areas. The bead contact site is defined as 2 o’clock.

Example:

Based on this, you can create various dartboards depending on (1) the chosen time interval (e.g. bead contact (0 seconds) to 5 seconds after bead contact) and (2) the selected subset of cells.
After running the main-script, you need to run the script “DartboardPlotGUI.py” in order to create your dartboards. You can either choose the “per-frame”- or the “per-second”-representation.