The aim of this procedure is to characterize species typical behaviors in mice. First burrowing behavior is studied by filling a tube with material and measuring how much is removed by the animal. Nest nestlets are placed in the cage and the completeness of the nest is quantified as a measure of nesting behavior.
Hoarding behavior is examined by placing a mouse in a box with access to a tunnel filled with food pellets and measuring how much the animal retrieves from the tunnel. The results from this series of tests show whether the mice perform their activities of daily living. Normally, The implications of this technique can extend towards the search for treatments for dementia because functionally similar behaviors are impaired in both a mouse and in man the species.
Typical behaviors in the mouse can be likened to the activities of daily living of humans even. And the first effects of Alzheimer's disease are to inhibit the performance of normal activities of daily living, like making your breakfast, doing up your shoe laces, planning a meal, going on a shopping trip. And with our model Alzheimer mice, we find that the species typical behaviors are very much inhibited.
So here we have a direct model, a homologous model almost between activities of daily living as seen in patients with Alzheimer's at home and in the clinic, and the inhibition of species. Typical behaviors in the mouse Construct a borrow from plastic pipe, 68 millimeters in diameter, and 20 centimeters in length. Seal one end with a plug made of 12 millimeters of MDF.
Next drill, two holes, one centimeter from the open end of the burrowing tube at an angle of 90 degrees. Insert a five centimeter long machine screw into each hole and tighten them into place. The tube should now be elevated approximately three centimeters off the floor.
On one end, fill the burrow with 200 grams of food pellets and place it in the home cage for habitation overnight. If the mice are housed in groups, habituation will be quicker and more thorough due to the social facilitation effect. However, baseline tests on individually housed mice should still be run.
Subsequently, non-food substances can also be used to measure burrowing behavior. Some examples include clay balls, pea shingles, and sand. After the animals are habituated, place a full burrow into the test cage around 4:00 PM to run a baseline test.
It is recommended to run two baseline tests, 48 hours apart. Two hours later. Measure the weight of the material left in the burrow by emptying the contents into a tared container.
Return the unborrowed material into the tube and place back into the home cage the next morning. Remove the tube and weigh any remaining material for testing. Repeat this procedure at least 48 hours after the last baseline measurement.
C 57 black six mice typically burrow around 70 grams in the first two hours and near 200 grams overnight. Hippocampal lesion mice often burrow less than five grams. Pion disease inhibits burrowing, as does lipopolysaccharide.
Administration burrowing can detect pion disease at 10 to 12 weeks after injection of diseased brain homogenate, whereas clinical signs only appear at 22 weeks. Borrowing has been shown to be sensitive to strain differences and knockout of potassium ion channel subunits. To measure nesting behavior, set up individual cages and cover the floor with bedding material 0.5 centimeters.
Deep place a five centimeter square of pressed cotton batting called a nest lit into each cage. Place one mouse into each nesting cage about one hour before the dark phase, and assess the results. The next morning.
Weigh the amount of un torn nest lit and assess the nest on a five point scale. A score of one is given when the nest lit is largely untouched and a five is awarded to a near perfect nest with greater than 90%of the nest lit torn up. Both males and females make nests as their purpose is thermo regulation as well as being associated with reproduction.
The C 57 black six mice nest scores for males and females are in the same range. Although we have not done a controlled comparison in a single most C 57 black six mice score four to five on nest construction. But when the hippocampus is lesioned, the median score would be round two.
A score of three is unlikely to be exceeded. To measure hoarding behavior, prepare the box that will serve as home base by inserting a water bottle and drilling a hole into the side where the hoarding tube will attach. Make a hoarding tube by rolling a 45 centimeter length of wire mesh around a 40 millimeter diameter tube.
Secure it with Allen clips or wire twists. Then push fit it onto a 10 centimeter length of 40 millimeter black tube. Next, connect the hoarding tube to the box prepared earlier and block the proximal end with a removable wooden plug.
Prepare the home box with a cardboard tunnel and soiled bedding from the home cage. Be sure that access to the hoarding tube is prevented. Place the mouse into the box early in the day for habituation later, remove the hoarding tube and fill the distal end with a mixture of large and small food pellets, totaling 100 grams.
Just before the start of the dark phase. Remove the wooden plug to allow the mouse access to the hoarding tube the next morning. Again, timing is not critical.
Collect and weigh the food pellets which have been hoarded into the home base box. Using female C 57 black six mice. The median amount hoarded would be around 50 to 70 grams.
Hippocampal lesions strongly suppress hoarding, whereas prefrontal cortex lesions have only a weak effect. After watching this video, you should have a good understanding of how to assess species typical behaviors in the mass.
