Brownian motion tracks


I am using LAP tracker in TrackMate to track movement (speed and displacement) of motor proteins. The majority of tracks in the output file are generated from particles (motors) undergoing Brownian motion and I wonder whether there is a way to filter out these particles prior to track analysis. Thanks!

Hi @phook

This is a tricky but interesting question.

If your tracks are robust and long enough, I would turn to MSD analysis (shameless ads).

For instance by fitting the log-log plot of the MSD vs delay, you can classify your tracks as being either brownian or transported, depending on the slope of the log-log curve (~1 = brownian, ~2 = transported).

In the link I gave above you will find a tutorial about how to perform this analysis in MATLAB. We used it in this paper to prove that our NEMO particles were attached to the membrane of cells.

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Many thanks @tinevez!