Reading 5: Natural Proteins in Brain Wipe 'Fear' Slate Clean

READING PASSAGE 5

You should spend about 20 minutes on Questions 1 – 8 which are based on Reading 5.

Natural Proteins in Brain Wipe 'Fear' Slate Clean

A

According to a recent study, the brain contains naturally-occurring substances that can wipe away fearful memories and with time may help soften the jolt of fear that can become associated with innocuous triggers.

B

The compounds are known as cannabinoids, and they share some similarities with the active ingredient in marijuana, THC. Mice that lacked a particular cannabinoid receptor in the brain stayed forever fearful of a certain sound that once was accompanied by an electric shock. In contrast, normal mice quickly lost their fear of the sound if it was no longer heard in tandem with the painful jolt.

C

The discovery may lead to a better understanding, and perhaps treatment, for people who experience post-traumatic stress disorder (PTSD)--a condition that can affect survivors of natural disasters, violent crimes and serious accidents. Symptoms of PTSD include flashbacks to the trauma, nightmares and emotional withdrawal.

D

In the study, Dr. Beat Lutz of the Max Planck Institute of Psychiatry in Munich, Germany and colleagues looked at mice genetically engineered to lack a particular cannabinoid receptor known as CB1. The researchers conditioned the mice to associate a sound with an electric shock. The mice were repeatedly exposed to the sound and the shock for several days. All of the mice that lacked CB1, as well as normal mice, developed a fear response to the sound.

E

The mice were later exposed to the sound without the shock and the researchers noted a different response in those lacking CB1. The normal mice "quickly recovered from (their) fear reaction," Lutz explained. In contrast the CB1-deficient mice, showed little reduction in fear and seemed unable to forget their past experience.

F

"Until now, the function of the endogenous cannabinoid system in memory processing has not been clear," Lutz said. "Our work could assign, for the first time, a specific function of memory processing to the endogenous cannabinoid system--extinction of aversive memories."

G

With regard to people, the authors note that ordinarily healthy people are equipped with "balanced" emotional responses to potentially dangerous situations. For example, if a person sees a poisonous snake, they relax relatively quickly once the imminent threat of being bitten has passed. An individual who has a phobia, on the other hand, cannot adapt to such situations and may develop an uncontrollable over-reaction, which could lead to an anxiety or panic attack. Similarly, individuals with PTSD may have uncontrollable emotional reactions to triggers that others might find innocuous.

H

"We think that our work could stimulate novel therapeutic approaches for the treatment of phobias or post-traumatic stress disorder," Lutz added. However, Lutz stressed, "we do not recommend to smoke marijuana to get rid of bad memories or to treat PTSD or phobics."

I

The compounds found in marijuana are unlikely to have the same effect because they are not specific enough for these receptors. The active ingredient in marijuana, THC, binds to all cannabinoid receptors in the body, irrespective of whether or not they are involved in extinction in aversive memories. However, it might be possible that the combined action of psychiatrist or trained psychologists together with pharmacological interventions targeting the endogenous cannabinoid system may lead to novel therapeutic concepts to treat above mentioned conditions.

Questions 1 – 4

Answer questions 1 – 4 using NO MORE THAN FOUR WORDS from the passage.

Write your answers in boxes 1 – 4 on your answer sheet.

1. What is the naturally-occurring substance in the brain that can wipe away fearful memories?

2. Flashbacks to trauma, nightmares and emotional withdrawal are symptoms of what?

3. Which mice showed little reduction in fear and seemed unable to forget their past experience?

4. With regard to potentially dangerous situations, what are ordinarily healthy people

equipped with?

Questions 5 – 7

Do the following statements agree with the views of the writer in Reading 5? In boxes 5 – 7 on your answer sheet write

          YES                     if the statement agrees with the writer

          NO                       if the statement does not agree with the writer.

          NOT GIVEN       if there is no information about this in the passage

5. According to Lutz, their work has found therapeutic approaches for the treatment of phobias or PTSD.

6. Lutz and his colleagues did not suggest that people should smoke marihuana to get rid of bad memories or to treat PTSD or phobics.

7. The findings of the study will help a drowning person overcome the fear of water.

Questions 8 – 9

Choose the appropriate letter A – D and write your answers in boxes 8 – 9 on your answer sheet.

39. When mice were repeatedly exposed to a sound and an electric shock, …

A. only the mice that lacked CB1 developed a fear response to the sound.

B. only normal mice developed a fear response to the sound.

C. both groups of mice developed a fear response to the sound.

D. neither of the two groups developed a fear response to the sound.

40. When a normal person sees a poisonous snake, he …

A. is frightened at first but relax quickly when the threat is gone.

B. remains fearful of the snake for ever.

C. does not respond to the situation.

D. will try to catch the snake.