D - Skilled Adult Motor Behavior
Objectives:
To describe prehension
To describe skilled food handling
To describe skilled forelimb reaching behaviors
To describe skilled walking behaviors and hindlimb movements
To describe the sequence of movements
Introduction:
Last week we examined a number of basic innate behaviors. Rats, like humans, can learn a number of difficult behaviors. These skilled behaviors improve with practice. Being able to quantify these behaviors is useful for understanding neural plasticity of the systems underlying these behaviors (e.g., Kleim et al., 2004). Additionally, some general motor behaviors are resistant to some types of brain damage, such as stroke. Skilled behaviors are often more sensitive to detect deficits following some insult to the brain. Two of the most common behaviors are skilled reaching and walking along a horizontal ladder.
Procedure:
Preparation:
Read chapters 15 in the Behavior of the Laboratory Rat book before this week’s lab. Rats may need some pretraining on the reaching task, so discuss this with your TA to see haw you can participate in this task. Have the rat food deprived for about 3 hours before the lab so that it is motivated to handle food items. Make sure that it has had experience with the food pellets to be used in the task. Palatable pellets may help motive the rat further.
Tests: Food Handling
Give the rat a piece of rice, a froot loop or a piece of rat chow.
Observe how the rat holds each type of food and how it brings it to its mouth.
Single Pellet Reaching
Place the rat in the reaching chamber. Place a number of pellets centered on the platform at the reaching slit. Watch the rat reach for them. Which paw does it use? Observe the order of movements. Videotaping the reaching behavior may make it easier to observe each individual component of the reaching.
Once the preferred paw is determined, place a pellet to the side of the slit on the same side as its preferred paw, forcing it to use its non-preferred paw.
After the rat retrieves the pellet, observe the movements that bring the pellet to the mouth.
Drop a pellet at the back of the chamber to get the rat to turn around to reset. Place another pellet on the platform by the slit while it is turned around.
If this lab can be done over a number of days, record the percent success each day (number of pellets retrieved, number of pellets retrieved without missing)
Horizontal ladder
Place the rat at one end of the horizontal ladder and its homecage or a dark chamber at the other end. Videotape the rat as it runs from one end to the other
Observe how it places its paws on the rungs. Count the number of time is misses, slips or needs to reposition its paws.
Increase the difficulty by randomly pulling out 10 rungs (never more than 2 adjacent rungs) and compare the number of errors and time to cross to trials where no rungs are removed.
If this lab can be done over a number of days, compare the number and types of errors each day.
References:
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