Rotarod

 
Rotarod performance is measured using a computerized rotarod system (San Diego Instruments, San Diego, CA) to test the ability of mice to maintain balance on a rotating rod.  The entire rotarod apparatus is kept and run in a laminar flow hood.  Up to four mice are placed on the rod within their individual lanes in the rotarod enclosure.  The four animal compartments are separated to prevent the mice from having visual or physical interactions.  The rod is positioned one and a half feet above the floor of the lower compartment as an incentive to remain on the rod.  The lower compartment of the rotarod apparatus is enclosed to prevent the animals from escaping after completing the task.  Seven photobeams are embedded in each of the four lanes of the rotarod enclosure, consisting of detectors and emitters.  The body of the mouse on the rotarod breaks several of the seven photobeams; the exact number depending on the orientation of the mouse.  Software tracks the photobeam breaks during the animal’s participation in the task.  Once the mouse falls from the rotarod, no beam is broken and the animal’s final run time is recorded.  When the photobeams in all four lanes are unbroken, the rod stops rotating and the final time for each of the animals is reported and saved to a Microsoft Excel file.  A typical experiment takes four days to complete: one orientation day followed by three test days consisting of three runs per day.  The assay is therefore an assessment of performance learning in addition to an evaluation of motor function.

Variables
Rod acceleration speed
Rod rotation of clockwise or counterclockwise
Maximum rotation speed
Passive rotation documentation: defined as a mouse slipping but not falling off the rotating rod.  Beams that go unbroken for fewer than 5 seconds signal the software to record run time on the rod after the period as “passive.”

Video Footage
(Filmed Vertically)