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Remembering What Matters

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PIECES OF MIND: Remembering What Matters

Neurobiologist James McGaugh is sometimes called "Mr. Amygdala" for his work with this almond-shaped structure in the forebrain. Intrigued by questions of how memories are made, he has studied the brain for more than 40 years. Through his experiments, McGaugh has found that an emotional response can enhance memory retention. Using PET scans to look inside the brain as memories are formed, McGaugh has discovered that the amygdala helps the brain remember what matters.

Curriculum Links
What Is a Pet Scan?
Activity: Brainstorming



brain organization

human brain


mental disorders


human brain,


imaging techniques


A PET scan is not an x-ray of your pet -- though perhaps it would be interesting to find out how the brains of cats and dogs and other animals work while sleeping and dreaming!

As you see on "Pieces of Mind," the use of PET (positron emission tomography) imaging has given researchers a tool to look inside the brain. Researchers can study the brain while we are learning, talking, remembering, thinking.

The PET technique uses radioactive elements to produce images of the inside of the body or brain. The person whose brain will be scanned drinks a simple glucose (sugar) solution tagged with a radioactive element. As the solution moves into the brain, it gives off particles like x-rays that allow the computer to trace their location on a color monitor. The more active the brain is, the more it uses the sugar solution. The greater the use of glucose, the brighter those areas glow. During a PET scan, the researchers may vary the person's exposure to sound or sight to watch for changes in the brain's image.

PET scans are featured in several stories in "Pieces of Mind," including this one on James McGaugh's work, which investigates the role of the amygdala. McGaugh uses the PET scan technique to actually peek inside the brain as memories are formed!

PET scans are now used to identify different areas of the brain used for sight, sound and speech, so researchers can actually "see" what a thought looks like. PET scans are also being used to help explain what is happening inside the brains of people with Alzheimer's, schizophrenia and other diseases. A PET scan of a person with severe Alzheimer's indicates diminished brain activity.


After you watch the show, brainstorm brain activities you think a PET scan could be used for. Perhaps your idea will one day be part of an experiment, as we continue to learn more about the human brain.


  • What might be the evolutionary advantages of memories enhanced by an emotional response?
  • How many of your experiences today can you recall? Of those you remember, are there some with greater emotional significance?


Scientific American Frontiers
Fall 1990 to Spring 2000
Sponsored by GTE Corporation,
now a part of Verizon Communications Inc.