V4 Focus Failures

[Mitch de Snoo]

I am experiencing focuses changes with some of my miniscope recordings, and I am currently out of ideas on how to troubleshoot it. Rapid changes in focus are happening throughout the course of a recording where the image pops out of focus and quickly returns to the same focus. This link (focus_failure_examples_smaller_files) has an example from a recording I took yesterday.

 

This focus problem only happens during behaviour in a spatial foraging task where the mouse is navigating on an 80 cm diameter circular board. I have not been able to able to recreate the issue with the scope not connected to a mouse, nor did I have any issues during 10 min homecage recordings of the same mice. In the spatial foraging task, I am using a NeuroTek commutator connected with a 1 mm thick 3 foot coaxial cable and the DAQ is above the board and commutator in the centre of the room and uses a 12 foot USB cable to connect to the computer. I have suspected each of these components, however, the problem persist even if I switch to no commutator, short USB cables, LabMaker thin coaxial. I have also tried two different computers and finally a second newly assembled miniscope but continue to see these focus shifts. 

 

Has anyone experienced and solved a similar issue? Any suggestions on how to proceed would be greatly appreciated!