Parallel Bar Motor Coordination
- The parallel bar apparatus consist of two parallel steel rods (0.5 cm diameter, 91 cm long) held between end platforms (15.5 x 17.8 cm). The rods are fastened with screws onto a rack of 28 grooved slots, spaced 0.5 cm apart, on each platform, thereby allowing the distance between bars to be manipulated. The platform and rods stand 63 cm above a floor of wood chip bedding.
- At the beginning of each testing day the subject will be placed on each platform for 30 s in order to acclimate the animal to the apparatus. The subject is then placed on the rods halfway between the platforms. The animal is placed on the rods in such a way to allow the animal to gain its balance and left paws are placed on one rod and right paws are placed on the other rod. The animal is allowed to decide which way it wants to travel, towards the left or right platform.
- Four successive alternating steps with the hind paws on the rods, constitutes a successful traversal. If the subject places both hind paws on one rod, falls, drags a paw, swings under the bars, or turns 360 degrees, the trial is considered unsuccessful and the subject is removed to the platform it was traveling towards. If the subject fails to move after a period of 5 m it is placed back in its home cage for one min and then placed back on the rods. If the subject fails to move after 3 m, testing is terminated for the day and the subject starts that day’s testing again on the following day.
- The initial distance between rods is set at 3.0 cm. Subjects are allowed up to five trials at a given width, with an intertrial interval of 5 to 10 s. If unsuccessful after 5 consecutive trials, testing is terminated for the day. Once successful at a given width, the rods are moved at increments of 0.5 cm while the subject remains on the platform. Subjects are tested up to a maximum of 15 trials per day, for 3 consecutive days. Each day the distance between the rods is set at the last successful width for each animal. The maximum width between rods successfully traversed and the ratio of successful traversal to total traversals is recorded and serves as measures of performance.