Sample Student Laboratory
Learning and Memory in Planaria (Dugesia dorotcephala)
An Experiment in Animal Behavior
This activity models inquiry based
student learning using the Black planaria (Dugesia dorotocephala).
Planaria are flatworms and a common organism for study in high school
biology classrooms. They live in fresh water and can be maintained
easily in culture in classrooms or in freshwater aquaria. The planaria
can be used in many inquiry-based activities. The educators in this study
trained planaria in in a T-maze ("Train-a-tray," from Carolina Biological
Supply) to turn right when given a stimulus of electrical shock.
This was done on a group given a conditioned stimulus (CS). There
were two control groups, one given no stimulus (NS), and one given random
stimulus(RS). Data was gathered that indicated that the CS
group was trained . Subsequently, they were chopped into
small pieces and fed to an untrained group of flatworms. The results
of the new recorded data indicated that the latter untrained
group were trained more quickly than the first group on which training
Notes to the Teacher:
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The "Train-a-tray" apparatus is relatively inexpensive and can be obtained
Biological Supply Co.
Use a 6V lantern battery and low-voltage wire instead of the AA battery
that comes with the kit. (The response of the planaria seems to be
Be sure to keep the control groups separate from the training group and
Move the planaria from the stock culture jars to the maze using a camel
Planaria move more easily on a layer of mucus. Allow some planaria
that are not
going to be trained to move around the apparatus before the beginning of
the experiment to put down a layer of mucus for the experimental animals.
Sometimes, planaria can be stubborn about moving. Use a camel hair
brush to touch them on the posterior end to get them
moving through the maze.
Materials & Equipment Needs:
Black planaria culture (D. dorotcephala) - at least 20-30 worms
Pond water or artificial pond water:
Make according the
Stock A Solution
Stock B Solution
133.0 g NaCl
3.8 g NaHCO3
26.6 g CaCl2
1.0 L distilled H2O
1.0L distilled H2O
10mL of Stock A solution and 10mL of Stock B solution to 1.0 gal of distilled
Low-voltage wire (bell wire)
Camel hair paint brush
Magnifying glass or dissecting microscope
Part 1: Conditioning Phase1) Separate planaria into four groups:
2) Place the worms from group NS into the maze for about 10 minutes
to get a layer of mucus on the maze.
No stimulus control group (NS)
Conditioned stimulus group (CS) (experimental group)
Random Stimulus group (RS)
Phase 2 group (P2)
3) One at a time place the worms from the CS group into the maze.
As they reach the branch of the maze give them an electrical shock if they
try to move left or go straight. Do not give the electrical stimulus
if the worm goes down the right branch.
4) Repeat this process 3-5 times for each worm in group CS.
5) Place each worm of group RS into the maze and give stimulus
at random times, sometimes if the worm goes right , sometimes if the worm
6) Repeat this process 3-5 times for each worm in group RS.
7) Repeat this entire process as close as possible to the same
time of day for one week.
8) Record the number of times that the CS group moves right under
Part 2: Transfer of Memory Phase
1) Using a scalpel, chop the worms of group CS into very small
pieces and place the pieces into the culture of the planaria labeled P2.
2) Repeat the above steps replacing the worms from group P2 for
those of CS.
3) Record data and compare the number of correct responses of
the P2 worms during the learning process with those of the original
Here's a look at some sample data:
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Data for Phase 2:
Phase 2 planaria completed the learning task successfully at a 70% (21
of 30 trials) rate after being fed the trained planaria on their first
try in the maze. Those wishing to complete this part of the inquiry
would obviously want to have further trials and more data in order to draw
conclusions. Many further extension activities could be planned from this