During chemotaxis, accurate movements tend to be faster movements. (*A*) Two-dimensional histograms displaying the log of the probability that a cell will make a movement during chemotaxis in the micropipette and microfluidic assay with a particular angle (*x* axis) and speed (*y* axis) represented in grayscale. Speed values are separated in bins 5 *μ*m/min wide; angles are in bins 15° wide and each bin is labeled with the upper limit for that bin. The heat-mapped insets show the difference between a given mutant and *wt*. Doubling and halving the bin widths had no appreciable effect on the general conclusion. Similar patterns can be seen in 2-D histograms of movements from the microfluidic device. (*B*) Scatter plot of the accuracy of *wt* movements versus their speed after normalized to each individual cell's mean speed. A linear fit (*red line*) indicates the correlation between accuracy and speed. (*C*) Correlation coefficients between each genotype's accuracy and normalized speed (as in *B*). Each correlation was found to be significant at *p* < 0.05 level. (*D*) A magnification of the plot from *B*. This plot, containing >99% of the total data, can be divided into four regions (labeled *I*, *II*, *III*, and *IV*) that describe the accuracy and speed of the cell (see text). (*E*) Percent of movements from each genotype with positive accuracy (quadrants *III* and *IV* in *D*). (*F*) Percent of accurate and inaccurate movements with faster than average speeds.

## PubMed Commons