The Modified Hole Board - Measuring Behavior, Cognition and Social Interaction in Mice and Rats

The overall goal of the following experiments is to measure unconditioned behavior of small laboratory mammals and analyze their cognitive abilities. This is achieved by placing the animals in the modified hole board to observe and score their unconditioned behavior with or without the presence of their cage mates. Additionally, a novel and familiar object or food pellet can be placed in the apparatus before testing, which can be used to measure object recognition or food intake inhibition.

A third application of this method is placing the animal in the cognitive version of the modified whole board where the reward is queued with a contrasting colored identifier In order to measure the cognitive abilities of the test subject, the results show a spectrum of unconditioned behavior. Since the method combines multiple behavioral dimensions in a single paradigm, which contains features from a traditional hole board and open field test, The main advantage of this technique is that it overcomes the disadvantages of a test battery by reducing the number of animals used, circumventing possible test order effects, and reducing time effect and costs. Testing should be performed in the regular housing room during the dark phase, the animal's most active phase for the purposes of this video testing is performed under bright light conditions.

Behavioral testing should be performed on animals that have been habituated to their environment and to handling by the experimenter. Place the board containing the cylinders in the middle of the experimental box. Then position a stage light above the board to create a contrast in light intensity between the board and the box, and increase the aversive character of the board.

To begin place the familiar object in the apparatus two centimeters apart from a novel object in the corner across from the starting point. Then remove the animal to be tested from the home cage and place it facing the wall in a specific corner of the apparatus. Allow the animal to explore freely for approximately five minutes.

Have an experienced observer score the behavioral parameters using behavioral scoring software. Use the parameters listed in this table and also measure the time the animal takes to approach the novel and familiar object or novel and familiar food item. Clean the apparatus with tap water and a paper towel after every trial.

In order to avoid a bias based on olfactory cues, place the group mates in the group compartment for 10 to 30 minutes before testing the experimental animal to allow for habitation. Then place the experimental animal in the test compartment and allow it to freely explore the modified whole board for five minutes or as long as required by your own protocol. Again, have an experienced observer live score the behavioral parameters using behavioral scoring software using the parameters listed in table one as before.

Before beginning this experiment familiarize the animals with a highly palatable reward. Here a piece of almond is used. Offer the reward with tweezers in the home cage once a day for two consecutive days before the experiment, insert a partition to reduce the size of the box to 50 by 50 centimeters.

For testing, mice, place a smaller board in the middle of the box. This diagram shows the setup of the modified hole board. Next scent, all 10 cylinders with a flavor that the animals are attracted to, such as vanilla and bait, all cylinders with the reward placed beneath a grid so that it cannot be removed.

Q3 cylinders with a colored ring that contrasts with the PVC and bait those cylinders with a removable reward. Again, place the animal in the same corner of the apparatus and have an experienced observer live score. The behavioral parameters using behavioral scoring software.

Measure the parameters listed in table two in addition to those previously shown in table one, with the exception of the parameters related to object recognition or food intake inhibition. Perform four training trials daily with a constant inter trial interval until a constant time for collection of all three almond pieces is established. Clean the apparatus with tap water and a paper towel after every trial in order to avoid a bias based on olfactory cues to test reversal learning.

Once the animal is fully trained, cue and bait three different cylinders or as many different cylinders as required by your own protocol and test the animal on the required number of trials. The first four images show results from the cognitive testing paradigm that measures the cognitive functioning of C 57 black six J mice with mild cerebral hypoxia ischemia labeled HI 45, severe hypoxia ischemia, labeled HI 75, and sham control mice. This graph shows the mean latency to complete the four trials of a testing day.

This graph shows the number of revisits to a bated hole on each testing day. A measure of short-term memory errors. Here, visits to non bated holes are shown.

This is a measure of long-term memory errors error. Here, the data for the number of omission errors are shown. An omission error is defined as the number of non visited baited cylinders.

To confirm that the I 45 group had no cognitive impairment, this group was tested against the sham controls. In a reversal task, the three bated holes were appointed to three different cylinders, and the animals were tested for four trials. The reversal effect becomes apparent when comparing the last trial of the first stage with the first trial of the reversal stage.

This image shows the latency to complete the trial for both groups and a clear overall treatment effect is evident. This means that there is impaired cognitive flexibility in the HI 45 group that was detectable using the modified whole board with the reversal task. After watching this video, you should have a good understanding of how to use the modified whole board in both the general and the cognitive version.