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| The Case: |
This is your brain, this is your brain on drugs |
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Susan has gone out with a group of her friends on a Friday
night. They are having a good time and
she decides to partake in the unknown substance that is going around. She does know that it is acting on either (.
monoamine levels, 2. amino acid levels, 3. lipid substances. Shortly after taking the drug she begins to
feel:
- euphoric, active, and talkative.
- mild euphoria, her anxiety has been reduced,
and she is slightly uncoordinated.
- mild analgesia and sedation, increased appetite, and a
distortion in the passage of time.
- (Can go on to describe the
effects of many other drugs...PCP, heroin, LSD).
How would you go about figuring out what she has taken?'
Or, instead of actually detailing Susan's behavior, the
students could then be told that one of their lab rats has been injected with
the same drug (maybe give them a list of potential drugs of injection to help
them narrow it down?), and that the other has been given a placebo. Each group will be dealing with a different
drug. They need to then determine what the woman has taken, based on rat
testing on the control and the experimental animal. Once they have actually tested their rats,
they can then look at brain region slides that have been prepared from other
rats that had been given the same drug (ICC and/or audoradiography). They would need to be able to interpret the stainings, and know what areas to examine to confirm their
hypotheses.
Case Author:
Kai McCormack Emory University:Center for Science Education
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Case Analysis
Students will need to uncover/investigate the following:
A. Drug Information
- cocaine: dopamine agonists. Cocaine binds with and deactivates the
dopamine transporter proteins, thus blocking the reuptake of dopamine once it has been released into the cleft.
Answer could also be amphetamines which are also dopamine agonists, but instead of acting on the transporters they cause the release of dopamine from the terminal buttons. Both drugs act on the system, increasing levels of dopamine in the nucleus. Nucleus acumbens is important for reward and
motor activity, thus the behavioral alterations seen when one takes cocaine.
- alcohol: acts as an indirect antagonist at NMDA sites (excitatory) and indirect agonists at GABA sites (binds
to the benzodiazepine binding sites—inhibitory). So, it increases GABA activity and decreases glutamate activity. NMDA antagonists produce sedative effects and interfere with cognition, like alcohol. GABA agonists also produce the anxiolyticeffects that alcohol does. It also increases the activity of the dopaminergic system by increasing the release of dopamine in the nucleus acumbens. This is what causes the rewarding feeling of alcohol. Both GABA and glutamate are EVERYWHERE.
- THC: acts on receptors, which act on calcium and potassium channels. THC also activates the release of dopamine in the nucleus acumbens. It is also affecting receptors in the hippocampus, thus affecting
memory. Acting as a lipid messenger.
- 5.6. any other drugs that you want to use, and their effects.
B. Experimental Design
Students will alos need to determine how to go about testing their rats. This will involve looking at rat literature to uncover typical behavioral testing techniques. They will also need to read about common behavioral effects of drugs on rats. They will need to then figure out what testing apparatus to use to test their animals, and then what behavior to code.
C. Brain region analysis
Students will also need to be familiar with recognizing different brain regions on stained slides, as well as how to interpret the stainings for activity.
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Option: Include a know / need to know chart like the one below:
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What do you know?
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What do you need to know?
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Learning Goals
Goal(s)
A. Understanding of
drug effects and systems effected
Students will need to piece together what they know about
drugs of abuse, with which systems they are acting on.
They will then need to investigate the neurotransmitter that
is being acted on, and HOW it is being acted on.
From this, they will need to examine WHERE in the brain this
is going on to explain the behavioral effects observed. Students may also need to examine how systems
interact with one another, like DA and THC.
B. Experimental Design
Students will also need to design an experiment to examine
drug effects. They will need to find
literature that details behavioral rat experiments as well as papers that
discuss the effects of drugs on rat behavior, and they will need to develop an ethogram to code the behaviors. Students will then need to run experiments on
their control and drugged rats, collect data, and analyze it.
C. Slides
Students will need to learn how to examine slides, and how
what they observe supports or refutes what they found in their experiment.
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Standards
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Investigations and Activities
Students will examine the effects of drugs on rodent behavior. Each group of students will have at least one control rat (saline injected) and at least one drug injected rats. Each group should focus on the effects of a different drug, depending on the # of groups. The students would be blind to which drug their rat(s) has, but should have a list of possibilities to help them design their experiments. They would need to design experiments to try and determine what drug the rats were given (open-field test, forced swim test, maze, open arm test, etc). Once the students have an idea of which drug their rat was given, they could then be told that they are going to look at slices of different brain regions, from similar rats that were exposed to the same drugs. Slices from different brain regions would be stained to show activation of the different neurotransmitters. The students would have to determine which brain sections to look at, and which stainings to examine to determine the drug that their rat was administered.
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Resources
Any search on neurobiology of addiction;
Students own textbook
Drug effect sites:
The Actions of Cocaine, Opiates, and Marijuana
http://www.nida.nih.gov/Teaching2/Teaching2.html
http://www.nida.nih.gov
http://www.health.org/
http://www.dd-database.org/
http://165.112.78.61/MOM/MOMindex.html (basic site)
Papers/sites that deal with ethogram development, rodent behavior and drug effects:
http://www.ratbehavior.org/
Martin and Bateson (1993).Measuring Behavior. Cambridge: Cambridge University Press.
Briner, W. (1996). Animal demonstrations of human conditions for the physiological psychology laboratory. Journal of Instructional Psychology, 23, 183-188.
Loke, W.H. (1989). Effects of caffeine on the motor activity of the laboratory rat: Physiological and psychological considerations. Psychologia, 32,135-142.
Schumacher, S. J. (1982). An alternative to the traditional physiological psychology laboratory: Identification of an unknown drug through behavioral testing. Teaching of Psychology, 9,239-241.
Sites that deal with brain structure, stainings, etc:
http://www.neurotransmitter.net/
http://jeb.biologists.org/cgi/reprint/196/1/283.pdf
For the instructor: use of rats in lab testing:
http://www.arches.uga.edu/~kaim/teaching_poster-1.pdf
Students will usually obtain additional references or resources
to help answer or explore their questions. |
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Special Data Items
If students couldn't run experiments on rats, the instructor could give different data sets (made up for purposes of this experiment) in excel or spss that measure different behavioral
outcomes of the rats on the different drugs. The students would then have to analyze and
interpret the data, and use their interpretations to evaluate the brain slices.
Link to rat ethogram that I have at home.
Link of behavioral scoring sheet that I have at home.
Link to slides?
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Student Products
Individually, each students should
write a brief lab report detailing their experimental design, findings, and
descriptions/conclustions regarding the effects of the drug their rat was on.
The lab report should contain the elements of a paper, an
intro which briefly covers the need to evaluate the effects of drugs on the
brain and behavior, a methods section which details how they are going to test
their rats behavior, a results section detailing their behavioral findings, and
a discussion section discussing their conclusions, and the effects of the drugsat the brain level.
Each group will also prepare a poster which covers their
experiment, the drug their rat was on, and the effects of this drug on behavior
and the brain. These posters will be
presented to the group as a whole, and perhaps to high school seniors.
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Assessment and Evaluation Plan
Evaluation will occur at the lab level, as well as at the report and poster level. Guidelines will need to be created on how to grade the reports and the posters. Students may also evaluate each others poster for content and clarity.
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Implementation
The case itself could be done in one day during lecture time. Students would then need to do research on their own time to determine how to test their rats, and how to code behavior. Once this has been established, students would need to test their rats in lab (1-2 days). After the testing, students would need time to examine the data. Another lab period could be used for them to study slides of rat brain sections. Out of class time would then be needed for lab report creation, as well as for poster creation. Finally posters would be presented in a class or lab period.
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Course name:
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Brain and Behavior
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Likely sequence in
syllabus:
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After the discussion about neurotransmitters, anatomy, and drugs of abuse
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Time during term:
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This usually falls towards the middle to the end of the semester
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Duration:
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2 class day, 3-4 lab days, quite a bit of out of class research time
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Setting:
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Class and Lab
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Students in course:
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24-30, juniors and/or seniors
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Collaborative elements:
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Groups of 3-4 to produce poster
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Additional notes:
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Credits
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