Addicted Brain ChangesNew research is overturning previous thoughts about how addiction permanently changes the brain. Researchers hope these new insights might lead to new ways of treating addicts. Interviewee: Christopher Cowan, University of Texas, Southwestern Medical Center Copyright © ScienCentral, Inc. Our brain is an ever-changing biological system. This video shows that addiction to drugs is associated with substantial changes to the wiring of the brain. Tiny branches on neurons called spines increase in number when we become addicted. That is a fact, but the research questions ask why they increase and what do they do. |
| 1. You didn’t read about “spines” in your textbook, but spines are tiny branches from much larger branches that make up the portion of the neuron that receives messages from other neurons. Consider the four structural regions of the neuron discussed on page 93. Which one of these do you think grows spines to increase its receptive field? |
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| 2. The video explains that early researchers saw that an increase in use of addictive drugs was associated with an increase in the number of these spines. In technical terms, there was a positive correlation between number of spines and amount of drug usage. They concluded that the spines must cause addictions. What did you learn in Chapter 2 (see pages 40–43) about correlation and causality that might apply to this study? |
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| 3. The end of Chapter 3 discusses a property of the brain called “plasticity.” Do the brain changes discussed in this video illustrate plasticity? Explain your answer. |
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4. This study is a great example of experimental reasoning, though it is a little difficult to sort out at first. Here are the facts: - Cocaine use reduces the amount of the protein.
- The protein inhibits formation of spines.
Therefore: More cocaine => less protein => more spines. Hypothesis: The protein is the common cause of addiction and spine formation. If this hypothesis is correct, then if you increase the amount of the protein: - Fewer spines should form.
- Addictive behaviors should decrease.
So the researchers injected the mice with the protein. Were their predictions confirmed? Explain. |
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Twin DNA DifferencesGeneticists are discovering that identical twins don't have identical DNA. As this ScienCentral News video explains, this surprising research could help scientists better understand genetic diseases in the rest of us. Interviewees: Julia and Claire Calzonetti, identical twins; Jan Dumanski, University of Alabama at Birmingham Copyright © ScienCentral, Inc. |
| 5. Dr. Dumanski says that he and his colleagues are challenging a “dogma” about twin DNA. What is this dogma? |
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| 6. Dr. Dumanski confirmed the idea that twins’ DNA shows identical gene sequences, but that twins may differ in the number of copies of some genes. Your textbook briefly mentions another way that the DNA of twins can be different (see “Genes Affect Behavior,” pages 83–87). What is the other factor limiting the similarity of twins’ genes? |
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| 7. As explained in your textbook (pages 85–90), twin studies by behavior genetics researchers rely on differences between monozygotic and dizygotic twins to separate influences from genes versus experience on behavior. Explain how the research reported in this video may complicate the work of behavior geneticists. |
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Does pleasure get old?They say youth is wasted on the young, but when it comes to pleasure chemicals in our brains, the opposite may be true. A study released today shows that there is a drastic change in how our brains respond to pleasure and reward as we age. Interviewee: Karen Berman, National Institute of Mental Health Copyright © ScienCentral, Inc. Additional footage courtesy Brookhaven National Laboratory. We’re all aware that people tend to change as they get older. Things that once brought us pleasure are not as appealing and we can develop new interests and passions. This video suggests that some of these changes may involve areas of the brain and the way they respond to natural neurotransmitters. |
| 8. Which one of the neurotransmitters described in the textbook (“Neurotransmitters Influence Mind and Behavior,” pages 98–102) is discussed in this video? What is the function of this neurotransmitter? |
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| 9. Based on brain images in the video and your understanding of the functions of each of the lobes of the cortex, which of the four lobes of the cortex is the one the researchers looked at when they scanned the “thinking part of the brain” as it “responded to anticipating and then winning money”? |
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| 10. The researchers measured dopamine levels and activity in “reward centers” of the brain. Was there a positive or negative correlation between dopamine levels and activity in the pleasure centers for young participants? Was the correlation positive or negative for older participants? What did they originally expect for older participants? |
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Hearing MotionImagine if words created a taste in your mouth, or music generated bursts of color. Some people have a rare condition called synesthesia, where their senses are somewhat crossed. Now scientists have found a new type of that condition: people who “hear” motion. Interviewees: Melissa Saenz, Caltech; Johannes Pulst-Korenberg Copyright © ScienCentral, Inc. We usually assume that each of our senses leads to its own unique type of mental experience. The phenomenon of synesthesia is shaking up this idea. |
| 11. In the discussion of synesthesia in this chapter (“The Puzzle of Synesthesia,” pages 124–125), Dr. V. S. Ramachandran’s explanation of synesthesia is discussed. His theory relates to color/number synesthesia, but, extending his theory to sound and motion, what would he say is the reason for the experience of the subject of this video? |
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| 12. It is fine to say you “hear motion,” but proving that this is not just some sort of hallucination is more difficult. Dr. Saenz devised an experiment to see if this motion/sound synesthesia could be scientifically validated. She recruited people with and without this type of synesthesia to be in her study. What was her control condition? Did the groups differ in their performance on this control task? |
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| 13. For the other (treatment) condition, the two groups did a different task. What was this task, and which group did better? |
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| 14. What would be the advantage of having synesthesia in this task? |
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