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For
years, scientists thought that brain cells did not
divide to produce new cells. However, ideas (like
brain cells) do change. Today, research has shown
that not only does the brain continually rewire, but
regions of the brain can create brand new cells!
In
“Grow
Your Own Brain,” you learned how changes in surroundings
and activities can boost brain growth. In the show,
you saw how an enriched environment resulted in the
creation of new neurons. You also observed how plain
old exercise increases the brain growth of running
mice. But can extra neurons really give us an edge
in thinking? That's what scientists believe based
on evidence from new research. Thinking power seems
to be directly related to the number of connections
made by brain cells. It is these connections that
build the paths through which thoughts travel. The
more connections, the more possible routes. The more
routes, the more powerful the brain.
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OBJECTIVE
In this activity you will learn more about the brain and
it's connections. You will then conduct an experiment to learn
about stimulus and response.
This
activity page will offer:
-
Background in learning brain structure and neural connections
- A
minds-on, puzzle-like experience in understanding geometric
progression
- A
lab experience in conditioning of guppies
PART
1- THE BRAIN GAME
BIG NUMBERS
Your brain contains about 100 billion cells. Each of these
cells may make up to 10,000 connections. Using these numbers,
the number of possible routes along which a brain message
might travel is ten to the 80th power. Ten to the 80th is
a huge number. How huge? Astronomical. This number is equal
to the estimated number of protons, neutrons, and electrons
that may exist in the universe!
MATERIALS
PROCEDURE

- Examine
these three patterns of dots and routes. How many possible
downward routes take you from the top dot to the bottom
row in each pattern?

-
Starting from the top and working your way down, how many
different routes spell the word “BRAIN”?
- How
many different routes spell the word “NEURON?
- How
does the number of possible routes increase as you
add an extra step to the path?
- What
do math teachers call this doubling effect?
- Make
a guess. How many possible routes would be found in
a 7-letter pattern?
- How
good are you at creating math puzzles?
Think about the type of challenge you'd like to create.
Then, write it up and share with a partner.
PART
2- RESTRUCTURING A FISH BRAIN
Can guppies be conditioned to exhibit certain responses,
like the mice you saw on Frontiers? Try this experiment
to find out.
MATERIALS
- Five
young guppies - around three weeks old*
- Fish
bowl (or plastic container)
- Cardboard
box that fits over the bowl
- Aquarium
net
- Fish
food flakes
- Journal
*These
can easily and economically be obtained from local pet stores.
Often called feeder guppies, these fish make excellent subjects
for behavior observations. When obtaining the guppies, ask
the salesperson for any extra tips on maintaining these
animals. At the end of the activity, the animals can be
returned to the pet store or given to students who maintain
tropical fish tanks.

PROCEDURE
- Clean
and thoroughly rinse a fish bowl using tap water. Do not
use dish detergent.
- Fill
the bowl with spring water (or water that has been appropriately
treated for maintaining tropical fish).
- Using
an aquarium net, carefully transfer five young guppies
to this observation bowl.
NOTE: Before transferring fish from one container to another,
make sure that the temperatures of both tanks are the
same. This is easily accomplished by leaving the bowls
in the same surroundings for several hours.
- Feed
the fish twice each day in bright light. Prior to feeding,
cover the bowl for 5 minutes with a light-tight box. As
soon as you remove the box, introduce into the tank one
large food flake per fish. After 30 minutes remove what
remains of the flake with the aquarium net.
- Repeat
this feeding later in the day.
- Observe
the behavior of the fish. How do the fish first behave
when you remove the light tight cover? Do they surface
or remain unaffected? Record your observations in a daily
journal.
- Repeat
the twice-a-day routine each day for two weeks (or until
the fish become fully conditioned)
- After
how many feedings did the fish surface immediately after
removing the tank cover?
QUESTIONS
-
What stimuli were used to condition the fish?
- What
response did the fish develop?
- How
long did it take for the response to develop?
-
How might fish of different ages behave?
PART
3-DESIGNING A METHOD OF INQUIRY
Suppose you wanted to uncover whether the richness of the
surroundings affects the quickness at which a fish can learn.
Using what you observed in the previous activity, design
a controlled experiment that would uncover if an enriched
environment affects learning speed.
- Develop
your inquiry strategy in terms of a controlled experiment.
- What
materials are needed for the control group?
- What
materials are needed for the experimental group?
- Can
you use the fish, which were trained in part 1 of the
activity? Why or why not?
- How
might an air bubbler affect the physical activity of the
fish? What effect might this have on learning?
Discuss
your experimental design with your instructor. What are
the strengths and weaknesses of your method of inquiry?
With your instructors approval (and needed materials), run
your experiment.
EXTENSIONS
- Suppose
you were an architect in charge of designing a play space
for toddlers. Using what you have learned from this Frontiers
segment, sketch blueprints for the design of the playspace.
For this activity, think real world. Keep the design safe,
practical, and affordable. With your instructor’s approval,
create a scale model of this space using paper, wood sticks,
and other art materials. Write up an explanation of what
you designed and why you designed it in that manner.
- HIGH
TECH CHALLENGE - Can you construct a virtual cage that
will stimulate the brain growth of rats? Using a desktop
design program, construct the layout for a highly-interactive
and stimulating rat cage. Your final product can be a
CAD drawing, paint file, or a clip which displays a virtual
walk-through of the surroundings. Write up an explanation
for the logic behind your design.
- Do
you think exercise affects your brain power? Have you
ever gotten up early, exercised and then taken a school
exam? If so, did morning activity affect your mood and
test score? If so, how? Do you think that this type of
limited exercise is more of an "attitude adjustment" technique
than a method for increasing thinking power? How can you
tell? Design a method of inquiry that might help you uncover
any connections between pre-exam exercise and test scores.
WEB LINKS
"Understanding Braille" and "Increasing Brainpower"
were contributed by Michael Dispezio, a Massachusetts-based
science writer and author of "Critical Thinking Puzzles"
and "Awesome Experiments in Light & Sound" (Sterling Publishing
Co., NY).
ANSWERS
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