The disappearing mouse pointer…

While designing an fMRI experiment, I ran into the problem that the mouse pointer disappears as soon as you start typing on a mac. In itself it is actually a handy feature — hiding the mouse pointer makes sense as long as you’re typing — but not in this particular case.

To synchronize the behavioral data with the fMRI data, a Siemens mri-scanner sends a pulse at the start of every scan, and this pulse is picked up by your mac as a ‘^’-keypress. This makes it really easy to log the scan times, but it also hides the mouse pointer every two seconds, which is extremely annoying for your participants if they have to use the mouse. I had to find a solution for this…

When google didn’t provide an answer, I came to realize that there is no way (as far as I know – please correct me if I’m wrong) to not hide the mouse pointer in OS X when you’re typing. To solve this, I came up with the following solution. First, download pinpoint, a tiny application from macchampion that displays a graphic around your mouse pointer. Then, pay the 10$ fee which allows you to add your own graphics, and add a standard mac cursor as a graphic. Now, make sure this cursor is displayed at the exact same location as your own mouse pointer, and you fixed your problem. While the real mouse pointer still disappears on every scanner pulse, the graphic stays in place, and your participants won’t even notice that the real pointer disappeared.